BAC Forum
General Boards => Technical Support => Topic started by: Tom Blad on June 24, 2017, 07:18:45 PM
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This is my first post to the forum and any help would be GREATLY appreciated. About a month ago we left on a short 50 mile trip to get an estimate on some cosmetic work to be done on the coach. Along the way I pulled off to make an outside adjustment and as I turned the key to off there was no response. No matter what position the key was in engine continued to run. We continued on to the original destination and upon arrival I turned the key to off and the engine stopped normally. 10 minutes later I started the engine and it was pulled into a parking area and shut off normally .The coach was left there for a week and when I attempted to start it to pull into the shop it would not turn over. Dash lights came on and low air chime sounded as it had lost air over the week. Both battery banks measured O.K. but it would not crank. Only a click from the front left bay starter solenoid and also a click from what seemed to be another solenoid located in the top of the battery compartment. Several more attempts were made an then after about 10 minutes I tried again and the engine turned over this time but would not start. Due to the problem of not being able to shut the engine down originally a new ignition was installed. More attempts were and it would alternate between turning over and not turning over but it never started. Finally gave up and had it towed to a Cat dealer 20 miles away.
The next day the tech tried to start it but it would not turn over. He worked on it tracing wires,etc, but could not get the engine to turn over He finally attached what he referred to a harness directly to the engine which I believe bypasses the coach electronics and the engine started right up. After a couple of days the tech indicated he had found the problem to be the rear start switch located in a rear bay. A couple of days later the dealer advised that a new switch had been installed and the tech had started the coach 12 to 15 times over the last couple of days and there were no problems. I also had them diagnose a check engine light which indicated one of the two speed/rpm sensors was bad and they replaced it. This entire process covered about a 2 week period of time and I subsequently picked up the coach and headed home. Stopped for fuel and restarted twice with no problems. Arrived home and parked it next to the house. A few hours later I went back out to start the coach and had the same no start problem. Would not turn over and would not start. NOT a happy day!
I read over the invoice and this is what it stated: Cause: inspected cranking system, attempted to connect to engine ECM, and found it will not communicate, check for blown fuses or breakers, connect an external power supply to ECM, crank engine with a manual start button. Engine starts and runs. Inspect wiring, tested for power and ground at a pin #52 and #53 and for switch power at pin #70 at ECM connector, no power at #70 pin, found remote switch at rear right side compartment to be sticking and needs replaced. Correction: replace remote switch with a new one, Reconnect OEM 70 pin and test sestem operation. Extra time spent on repair due to chassis design Repair complete. Segment 1 Total $524
I went back to the dealership and spoke with the tech and he was at a loss to explain the no start problem after the repair. He indicated he was kind of "running blind " since he had no manuals or schematics, but thought he had finally correctly identified the problem. (at the time I had no access to those schematics and manuals due to the prior theft of those items as well a many other items from the coach). The tech also said that he was able to recreate the no start situation prior to the repair by manipulating the switch. Also that after the repair he had started the coach 12-15 times over the next couple of days with no problems. The tech did seem to be very conscientious in his work and I do believe he was forthright in his explanations, but he was puzzled as to where or how to proceed further.
Since getting the coach home I have read most every post on the BAC forum and have found several similar but not identical situations. Based on reading those I have done the following:
1.The front start solenoid in the electrical bay was replaced with a new spare I have been carrying for several years and that did not solve the problem. I was a little puzzled however when the key was turned to accessory the solenoid made an audible click and I could feet it activate. When I checked the voltage it showed 12.7 with the ignition off and 0 when it was turned to accessory or start. I would have thought the opposite but I do not know how these things operate. I did not meter test the original solenoid before changing it out but I could hear and feel it activate as the switch was turned to accessory.
2.Both battery banks showed fully charged.
3.I located the ground from the house batteries to the frame and it appears good. I was not able to see where the chassis batteries ground to the frame as it is bundled with several other cables and goes towards goes the front of the coach. I could not trace that cable.
4.Another poster described a similar problem with his 2006 Patriot Thunder and it was solved by replacing the "PCB 1 board " (starter control board). My coach is a 2000 Patriot Thunder with 2 slides, 40 ft. and the Cat C-12 engine. Unfortunately I have not been able to find such a board and not even sure if I have one on my coach.
5.I partially pulled the rear start switch to get a better look at it and there were no loose wires or anything out of order that I could see.
So there you have it. This has been going on now ($$$$) for over a month with no end in sight. Sorry for the long post but I wanted to include all of the information that might be relevant and what I have tried to do to solve the problem.
Needless to say any advice, opinions, etc. would be GREATLY appreciated!
Tom Blad
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Tom,
Welcome to the Forum! Hopefully we can give you some ideas. The problem with the engine not shutting down when the key is turned off is an intermittent one that I had on my 00 Marquis and know of one other 00 Marquis owner (now 2 counting you) that had the same problem. The “fix” was to shut the dash AC off. The engine would then stop. Never was able to trace what the actual cause was since it happened very infrequently.
The ignition solenoid in the front electrical bay will activate when you turn the key to ACC or ON as it supplies 12v to all the accessories, etc. so the clicking you hear is normal. You should see 12V on the battery side of the solenoid (large terminal on your left side) when the key is off and 12v on both sides with the key On/ACC. If the engine is not turning over it could be that the ignition switch in the dash is faulty. I think it is a standard GM ignition switch that should be available at any auto parts store. You could also have a faulty starter or starter solenoid. If the engine turns over but doesn’t start, the problem is probably air or fuel related.
Steve
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I had a similar problem to your failure to shut down issue. With Gerald's help I found that one of the wires on the 12vdc buss in the run bay (ignition on side) had 8 volts on it after turning the key off. It was enough to keep the engine running. It was a wire at the alternator that had shorted itself to a 12vdc line. I'm not a mechanic so I had one do the "greasy" stuff. As in my Navy days, I do the electronic stuff and if it gets too greasy I get help. I'm slowly learning though. I found those greasy guys are expensive! Good luck and welcome!
Jerry
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Thanks for the responses. In regards to the no shutdown, that was the first and only time that ever happened. I was not running the air at the time and it did shutdown normally when I reached my destination so at present I'm not too concerned about that especially since I can't get the beast to run at all. I checked the ignition solenoid and it does show 12+ volts on the battery side when off and 12+ volts on the other side with key on/acc.
As I mentioned in my post I had a new ignition switch put in the day that I had the first no start problem and it still would not start. When I had it at the CAT dealer I also had all filters changed but anyway it will not even turn over so I'm not even to the point where I can consider fuel problems unfortunately.
Is there an easy way to trouble shoot the starter? And am I right in thinking the starter has its own solenoid attached to the top of it? I am obviously not a mechanic but I do turn a wrench now and then. My motto is "first, do no harm" which I have learned the hard way!
Jerry, you are right about those greasy guys, but you can't live (or drive) without them. So far on this little project I'm for $1600 and still can't go anywhere!
Tom
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Tom,
Does you transmission console light up when the key is on? If not it is not getting power and the engine will not start. There is a fuse in the console the transmission panel is mounted in.
The starter should have a solenoid on it. Earlier chassis models also had a solenoid that powered the fuel pump and starter solenoid. It was mounted on the frame near the engine but not sure how yours is wired.
Steve
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For what it's column I would start with 2 checks.
1. When you turn the key on do the instruments become active?
2. Retrace what the mechanic did with the aux. start switch on wire 70
My coach does not have the rear run switch, how ever my previous one did. And the best I remember the main switch had to be turned on then you could use either start position. To me the aux. switch would be the place to start for power on wire 70 or what supplies power to the switch.
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Tom,
In your item one in your first note it is not clear exactly how you were doing the measurements, that is where the probes were, so it is hard to know exactly what was going on.
The solenoid in the electrical bay may still be the culprit especially if it was carried for some time in a damp location like the bottom of the electrical bay. The contacts could be oxidized or it could be a defective unit. A new one is not very expensive if you want to do an inexpensive change to rule it out. If you have ever turned the key to acc or start since the repairs have been done and the dash gauges have not come on every time then 95% chance it is that solenoid causing the issue. The next time the no start happens don't touch anything and go measure both copper busses to ground and see if you have 12V on both. If you do then try hold down the emergency start switch on the side console for 30 seconds and see if it then starts. That switch parallels all the batteries and if it starts it is likely you have a good solenoid and key switch, just not enough current to turn things over or engage the starter solenoid.
Ultimately what you need to know is if the electrical system is toggling on and off the voltage on the starter solenoid small wire terminals or not. If not then something is open in the wiring path (look to the front ignition solenoid or key switch), or if it is toggling but the voltage is low and will not fire the solenoid look to the wiring connections, starting batteries themselves, or the heavy battery cable connections from the chassis set. If the chassis batteries are weak they can cause this issue.
If you already spent $1600 and they did not fix this issue they should be doing a free repair and sourcing this problem in my humble opinion. Hope this helps.
Later Ed
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Thanks to all who have replied. Ed, you are right on the #1 item on my list regarding the solenoid. I don't think I tested it properly. Since then I have tested it as Steve suggested and with the key off I'm getting 12+ volts on the large left terminal and 0 on the remaining 3 terminals. With the key on I'm getting 12+ on one small terminal and 12+ volts on both large terminals. Based on that and hearing and feeling the audible click when turning the key I do believe the solenoid is working correctly. Also with the key on the low air light comes on, the red park brake light indicator comes on, speedometer flips all the way around and pegs out for 2-3 seconds and then returns to zero (this is normal),volt meter reads about 12.8, silverleaf lights and shows coolant temp at 68 degrees, fuel temp shows 66 degrees and intake manifold temp at 68 degrees, windshield wipers function as well as turn lights. Also with the switch off the genset starts as usual.
The transmission console does not light up when the key is on. Steve mentioned a fuse in transmission console but I have not been able to find one. I have located and took pictures of three different P C boards in that console which I will attach pictures of to this post. The two smaller ones were taped together near the rear of the console and the other was beneath and part of the shift selector panel. I have not been able to access the top side of the larger shift selector PC board. I will free it up when I can do so without breaking something. Most boards can be freed by removing a couple of screws, but this one has about 6 plastic pegs holding it together. Anyway, looking into that board from the side at this point it does not look like it contains any fuses.
In regards to another solenoid in the rear, I have located one just to the rear of the battery box which I will attache a photo of. It appears very similar to the solenoid in the front electrical bay but I have not been able to get any numbers from it as it appears the batteries will have to be removed to access it.
Joe,you mentioned pin #70 in regards to the rear switch. Would this be the hot wire going to one end of the remote switch? On my invoice the Cat mechanic stated " tested for power and ground at #52 and#53 and for switch power at pin #70 at ECM connector. At this point I am kind of lost. I don't know what or where the ECM is or what exactly it does. I found a heavy silver metal box measuring about 10" x 12" x 2" up in the console that holds the transmission control pad. Could this be the ECM? I think you are right about the operation of the remote switch. I used that switch once about 8-9 years ago and it did not start the next time I tried it. After it did start I never used that switch again. Also do you know if the two gauges in the rear start area (water temp and oil pressure light up when the compartment light switch is thrown? Mine does not light up and am wondering if there might not be any power going to that rear start compartment. I will be doing more checking on that.
Ed, the next time I have a no start condition will not be far off since it has not started since I returned from the Cat service. I did as you suggested and found that in measuring from copper busses I get I get 12+ on the hot side and 0 on the other side with ignition off. When key is turned on I get 12+ on both sides. I have also tried the boost switch and still no crank and no start. I will be attempting to test the starter solenoid itself and from there. I may have to wait till tomorrow as I am still recovering from the last day or two of twisting myself into the unnatural conditions to do this stuff!
Also thought I should mention the $1600 tab on the Cat work. A little ???? frustration is beginning to set in on us and in all fairness the $1600 included some other items such as coolant change and replacing a speed sensor, etc. I would still like to have had them offer some options but they were completely stumped. I just don't think they wanted the challange. We are attempting to do a complete update on the coach and thought we would start with the mechanicals and then on to the interior. So far we haven't even got a good start on the mechanicals so we are FAR FAR behind!
Eventually though we'll get on with it just as soon as we get the Beeve fired up!
I was going to attach the aforementioned pictures to this post, but would like to take a couple more pictures that might be helpful and attach to a separate post.
Thanks for the suggestions and help. We'll keep at it.
Tom Blad
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Tom,
This post may help re Allison fuse location. http://beaveramb.org/forum/index.php/topic,4631.msg35142.html#msg35142
Steve
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Tom,
Your ECM (engine control module) is bolted to the passenger's side of your engine block.
Gerald
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Steve,
Thanks for the link. Box was located just where the link indicated in the electrical bay. I guess I spent so much time fixated on the solenoid over the last couple of days that I didn't notice the box labeled "Allison". That's the good news. The bad news is I found two 10 amp fusses and both were good. I was sooo hoping to find a blown fuse but at least there was some progress made today. In the console beneath the shift pad there is another silver metal box with an Allison tag on it. It is labeled as an ECU. I plan to open it up tomorrow. Would you think there could be fusses in there?
And Gerald, thanks for the info. I found the ECM with no problem. Just didn't know what it looked like. Would this be where the Cat tech hooked up the harness to initially bypass the coach electronics to get it started?
Also as I mentioned in my earlier post I attempted to attach pictures of some of the boards, etc.that I located but an error code was displayed and the post never materialized. I'll try again later.
Thanks,
Tom
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Tom,
If you find that you can toggle the 12V on the starter solenoid with the key in the start position (like to see 12V on the solenoid but the harness will drop some voltage) I think the next step would be to hammer on the starter solenoid and see if it is sticking and see if it will then start. I am on the road so I check in on this one when I can...
Later Ed
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Tom, there are kb limits on each image (300 kb) and also the total per post (5000 kb) which is likely why you got the error message. In the General Boards section you'll find Forum Assistance, and under that we've created several help areas including how to deal with photos and such.
If using Windows, I've found the quickest way to downsize imagery is to open them in Paint, then choose the "Image" tab, then "Resize/Skew", and drop the image parameters from 100 down to about 25 percent, which will cut the data load to somewhere near what the Forum can manage. Then save each as a copy that you can use for emailing or post on the Forum. Windows 10's Paint skips a step, revealing a handy "Resize" option on the main page. For immediate use and convenience, I just put them on my desktop for easy locating when "browsing" from the Forum "Attachments and other options" button.
If using a Mac, instructions are there on the Forum Assistance site previously mentioned.
Joel
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Tom,
I'd definitely check both Allison boxes for fuses. If you can't find any in the second box then I'd go back to the first box and see if there is 12v at the fuses. As I mentioned earlier, if the Allision panel isn't getting power (lit up) the engine won't start.
Steve
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Still no light on the shift pad so no start. I checked inside the Allison black plastic box located in the electrical bay. The board inside is stamped as Allison Transmission 29509439. The board has 6 Bosch high capacity 12v spdt 50 amp relays # 0332209137 attached to it. On the board there is also printing in different places which says "IGN, main power, neutral start,and reverse warning" . I cannot tell which relay might be associated with which function. Also mounted on the board are two 10amp fuses. The fusses tested O.K. for continuity and showed no voltage whether the ignition switch was on accessory or start.There are also 16 metal pins/bridges that are mounted on the board and are linked to a total of 26 wires via 4 separate plug ins. Plug in numbers 1 and 2 have a total of 14 white labeled wires with designations such as engine brake common, ignition power, engine brake out, power to reverse relay, 357 to xsm neutral, 365 ecm common, 209 reverse relay out, battery power, 232 start, 232a start,etc. The other two plug ins contain a total of12 multi colored wires and are are wrapped in tape and covered with a plastic shield. I could not read the labeling on those wires if they had any labeling. The previously mentioned 16 metal bridges were tested for voltage and they are identified on the board as a,b,c,d,e,f,g,h,j,k,l,m,n,p,r,s. With the ignition switch off none of the bridges showed any voltage. When the ignition was turned to accessory, bridge b was the only one that showed any voltage which was measured 12.6 volts. When turning the ignition switch to start, bridge b showed 12.45 volts as did bridge f. That was all the testing on that that I have been able to do so far. Any ideas on how to test this board?
I did separate the multi wire connector between the transmission selector pad and the silver metal allison box both of which are located in the transmission console in the drivers area inside the coach. I will be checking continuity on the short wire run from the pad to the connector, and hope to open the silver metal box to check for fuses, etc.
As Ed suggested I went under the coach to check the starter and starter solenoid and found that it looks like the starter itself has a total of 4 larger cables all of which are attached to the same post on the end of the starter. Not sure where they go but they showed no power. The solenoid which is mounted on top of the starter has a total of 1 larger copper colored terminal which has constant power and tested 13 amps with ignition switch off and showed no change when the ignition was turned to start. I have not been able to test the other 3 smaller yellow wires. one of the smaller yellow wires is attached to the same terminal as the larger copper colored one. Any thoughts on what, if any reading I should be able to get from the 3 other yellow solenoid wires? I also gave the solenoid a couple of hard raps with a hammer and that did not produce any results. (it felt pretty good to do that though!).
Well, I'm off to attempt to access the silver metal Allison box and also to check the wiring on the remote rear switch and the nearby compartment light switch. Can anyone advise what this switch does since there are no lights in that compartment?
Thanks,
Tom
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Tom,
The transmission has to confirm it is in neutral before it will allow the engine to be turned over, so that is the main problem at hand to be fixed first.
As far as the starter, there is not much trouble shooting to be done until the keypad works and you then may not need to troubleshoot the starter if you can sort out why the display is not active.
Just a little info on the wiring on the starter, if you find you do need to go there. The large wire that is tied to the solenoid, that is powered on all the time, is the main 12V feed. One of the smaller yellow wires that is tied to the small solenoid terminals is tied to the key start contact that enables the starter to crank over. Between the key start switch and the starter solenoid, the transmission pad logic makes or breaks that electrical path based on whether neutral is confirmed. When the small yellow wire is energized from the key start contact to the solenoid, it powers a wire coil electro magnet that causes the starter gear to engage to the flywheel, and at that point it makes a large 12V contactor inside the starter solenoid connect the large 12v powered wire on the solenoid to the starter motor windings and armature and then cranking begins. The other large wires on the back of the starter are ground that have no voltage on them.
So the neutral switch has to be made first to enable the path. There is one more obscure possibility. Cat has an anti theft circuit, that if somehow it inadvertently was set to protect the coach, that could also disable starting.
Wish I knew more about the transmission logic and wiring but I never had to go there so hopefully there are better sources for help out there that can get you through that trouble shooting. Hope this helps.
Later Ed
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Tom,
One more thought.....Cat was able to get the rear run switch option to power up the coach. Have you checked to see if the rear start option still works and if it does, that must then power up the Allison pad. If that is true you could see what wire is toggling 12V on and off to that Allison control pad with the rear start that is not active from the front start and trace how that wire gets powered up from the wiring in the front of the coach. It may be that the rear start does not work now either, but thought this was worth a check.
Later Ed
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Ed,
The Cat tech initially could not get the engine to crank at all ( I also believe the shift pad was not lighting either) and he eventually connected a Cat harness to the engine. He said it started right up. I don't know if the trans pad lights up when it is started under these conditions or not. I am 99% sure that the pad was lit up when I started home with it as I remember checking to see if the red mode light was on as I was driving. At the time, of course I didn't know anything about the trans pad needing to be lit to function. He then thought he had found the problem to be in the rear start switch and could reproduce the problem by manipulating the rear start switch. He replaced that switch and felt the problem was solved. I suspect he started the engine from both the rear start and front start position but don''t know for sure. I have tried to start from both front and rear and it reacts the same way (no crank and trans pad does not light. I plan on going back to Cat today or tomorrow to clarify and also to see if they can offer any kind of off site assistance. The tech said that he started the engine several times over a couple of days and it started as it should. Then when I picked up the coach it also started as it should and also ran fine and started O.K. while fueling on the way home. The problem then began again after I got home and has been dead in the water since. I'm going to spend some time on the rear start area today and am contemplating replacing that rear switch along with the rear compartment light switch which is located right below the rear start switch. Don't know if they are wired together somehow or not. Need to see if there is any power at all going to that rear start area.
Thanks,
Tom
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I spoke with the Cat mechanic and he advised that once he changed the rear start switch the coach started right up. He started it from both the front and rear with no problems. He showed me the Cat harness he used to by pass the coach wiring and explained the pin# references he had on the invoice. Of main concern to him was pins 52, 53, and 70 (which in think is main power). Also the J19 which I believe is the communication link. I have also inspected both rear switches. The start switch looked good but the compartment lite switch had a broken terminal. I have ordered a new switch and will install in a few days. Don't know if that switch is in the start circuitry or not, but will replace it anyway. Does anybody know what this switch is supposed to do?
I have also located the ECM in the transmission console and will open it in a day or two to check for fusses. Very hard to get to it and to release the plugs. Also the two fusses in the VIM are good and I will change the 6 relays around that are in there to other positions to see if any of them are bad. Also the board beneath the shift pad has no fusses, but shows no outward signs of problem.
Does anyone know the route that the battery power travels to get to the VIM,ECU and transmission pad. Also how to determine which wires/pins to check for power. Does power go to ignition switch then to the VIM, then to the ECU, and transmission pad or does power go to the pad in a different order. I read on another forum where someone had a similar problem and eventually solved it by running a direct #10 gauge wire directly to the ECM or VIM and got power and solved the problem. Any ideas. Got to get that pad to light up.
Tom
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Tom,
If you haven’t yet, you may want to refer to the Marquis wiring diagrams at http://beaveramb.org/coach-assist-members-only-2/ located in the Private BAC Members Only board. The Coach Assist post has the hyperlink to access them. Although they are labeled for a 2003 Marquis, the wiring for all Magnum chassis units is very similar and used pretty much the same circuit numbers, etc.
Power is applied in parallel to the functions you are concerned about. The source is the ignition buss in the electrical bay under the driver.
• CB21= Engine ECU. It supplies power via wire 201 thru C4-1, C51-1 and C57-1 to the ECM relay.
• CB24=Xmission ECU. It goes to C5-11 via wire 202 to C42-1.
• CB27= Dash Inst Shifter Console. It supplies Instrument power via wire 211 to C4-19, Ignition Security System pwr via wire 614 to C4-24, and Ignition Pwr via wire 250 to C5-16.
The Circuit Breakers are thermal and trip when they get too hot and reset when they cool down. You can find the above in parts 2 & 3 of the Marquis diagrams
Also, there is a 20A fuse for the transmission VIM in the Fuse Module Tray (see diagram in Marquis Wiring section).
I suspect the pin #s the mechanic was referring to are on the engine ECM itself which does not appear to be covered in the diagrams above. I would verify the low amperage fuses in the Allison Control module before looking elsewhere as something happened between the shop and your trying to restart it. If you find a blown fuse, I’d check the area(s) the mechanic worked on for a bare wire that could momentarily short to ground.
Good Luck,
Steve
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Steve,
Thanks for the information. I did go to the coach assist section and downloaded all of the 2003 Marquis wiring information plus a couple of others. Have spent much of the day going over the material. Slow reading because I am not well versed in these matters. Very helpful. There are differences in Patriot Thunder and Marquis diagrams but since the wires are labeled I was able to identify most of the ones that might be relevant. I located what I believe to be the " fuse module tray" on sidewall of the battery compartment. There are 5 items located in there as follows:" ECM relay"The which appears to just be a 15 amp blade fuse. The second one is labeled as "service center" and is a 20 amp blade fuse. The third one is labeled "XSMN VIM" and is a 20 amp blade fuse, the fourth is labeled as event recorder and is a 20 amp blade fuse. The fifth appears to be a larger relay (Seimans) labeled ECMR. The fuses all looked good and tested good for continuity. I am not sure how to test the relay or if it is necessary.
I plan to remove the fuse tray from the wall of the battery compartment tomorrow and see what color wires lead out of it and if they are labeled and where they might terminate up front. Hopefully then I can test wires for continuity and power. I should have the two new switches for the rear start box tomorrow and get them installed. I still need to open the ECU silver metal box up front and check for fuses,etc. Once all of the above is completed I'll give it try again. Probably looking at couple of days to get this done.
Thanks,
Tom
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Tom,
No need to pull the fuse tray. Look on the page following the fuse tray diagram. All are 14awg white wires. I'll still suspect your problem is a blown low amperage fuse in the allison box.
Good Luck,
Steve
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Tom,
This thread might be helpful. http://beaveramb.org/forum/index.php/topic,4631.msg35142.html#msg35142
Steve
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I am still working on my no start problem. One of the previous posters on another thread solved a similar problem with
a new PCB 1 board (starter control board)? I have not been able to find one. Does anyone know the location of that board or does my 2000 Patriot even have one?
I have found the black plastic Allison box in the electrical bay. I believe it is called the VIM (vehicle interface module). I have also seen it referred to as the TCM, etc/ It has two 10 amp fuses inside which tested good. I also located the Allison ECU (also sometimes referred to as the main Allison computer). It is a silver clam shell metal 6" x 6" box which had two PCB boards inside. There are no fuses inside. There is a black plastic box directly beneath the shift selector pad containing a PCB and no fuses inside. I have found only 6 fuses so far. Two in the black VIM box and 4 in the battery box area fuse module tray. Seems like there should be more than 6 fuses. Am I overlooking some areas that might be relevant?
I have put in a new ignition switch up front and a new Comp light next to the new rear start switch. I doubt that the light switch is relevant but one of the terminals was broken so I replaced it. The ignition terminals and wires are labeled as follows: Ignition terminal connected to wire labeled ignition power, Ground terminal to wire labeled ground
Battery terminal connected to a wire labeled battery power to ignition, Accessory terminal connected to a wire labeled accessory, and SOL terminal connected to wire labeled start.I do not know where these wires go to. This is probably a real elementary statement but it seems logical that the whole starting process begins with the turning of the key, but I am not clear on routing of the power from there on. Which part of the Allison communicates with the other parts and in which order. Can anyone advise the routing of the power when the key is turned to start?
I am looking at replacing the solenoid in behind the battery compartment. Not sure if this solenoid is part of the starting circuity or not but when I attempt to start I can feel and hear the front electrical bay solenoid activate as well as another solenoid in the ceiling of the battery compartment. The third solenoid does not appear to be activated by anything. Unfortunately it looks like all the batteries must be removed in order to access that solenoid.
I am also replacing the two chassis batteries as they don't seem to hold a charge as well as they should overnight. I also have not been able to test power to the CAT installed rear start switch but will do that after I replace the aforementioned solenoid in a couple of days and get the batteries back in. I am also considering having the Allison shift pad, VIM, and ECU tested. Does anyone know if Allison dealers do this type of testing? I have a possible truck repair facility that will make onsite visit($$$$) and indicates that they have the necessary diagnostic tools and proprietary software for CAT and Allison and thinks they can probably solve the problem. I would like to take the three Allison transmission items and have them tested before I sign on for the onsite visit. Any ideas or suggestions would be welcome.
Thanks to all who have responded.
Tom
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I had a similar experience several years ago. The link below will take you to the entry where I finally got my coach to start.
http://beaveramb.org/forum/index.php/topic,2701.msg20280.html#msg20280
The pertinent paragraphs:
"After chatting with Ken at BCS for five minutes, we learned there are two fuses just under a small removable four inch square plate on the generator. One of those fuses, a mini auto-style 15a (blue) fuse was blown. Now the generator starts.
"Ken said the problem with the C-12 not starting is the transmission MUST report to the engine that it's in neutral. Remember, the transmission shift keypad would not light up. Under the keypad there is a black box, accessed by removing the vertical door that holds the map pocket. In that black box you will find fuses. One was blown. Now the keypad lights up and GUESS WHAT, the C-12 starts right up."
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Tom,
If all fuses are OK, check for 12v coming into a-fore mentioned transmission control boxes. I'd expect it to be on the 10 amp fuses. If 12v is present, sounds like it is one of the boxes. As I posted earlier, I think wire # 202 is 12v to transmission ECU. If not and no 12v, ID wire # so you know what you are looking for in electrical bay, etc.
Steve
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Well, a lot has been going on with the no start problem. Some good, some not good, and most not explainable.
We have replaced the following items: 1. Front electrical bay (start ) solenoid. 2. Ignition switch. 3. Rear start switch. 4. Comp. light switch in rear start area. 5. Solenoid located behind the battery compartment (the most inconvenient place you could ever put an item like this!) 6. New chassis batteries.
Also we have cleaned most every connection we came across although most looked to be O.K. except the rear comp light switch. Located all three Allison components (i.e Transmission shift selector pad, Transmission VIM, and main Transmission ECU). There are only two fuses total in the three components and they were 10 amps in the VIM box and both tested good. I believe these three components are functioning O.K. as I will explain later as we were eventually able to get the engine started. Also, there are four fuses in the fuse module tray which all tested good.
While doing the above listed things we began to identify and trace wires as Steve suggested previously. One of the things we discovered is that the wiring diagram that is attached to the inside of the electrical bay door is not accurate. For example, On the diagram CB22 says service board, XSMN, ECU, and VMS2. The wires connected to CB22 are actually labeled as #265 Ign Power VIM relay, #202 Ign ECU and #233 Ignition Power. Until we discovered this it made any tracing of the wires a futile effort. We finally identified the wire numbers and names on all the wires coming off he copper buses and will be tracing those as well as checking for continuity and power.
Another major problem has been getting the proper schematics. I have down loaded over 100 pages from the BAC fourm and other sources and have had no luck in finding schematics for a 2000 Patriot Thunder with the rear start feature. I realize that many of the schematics I have examined apply to more than one model of coach. For example many of the schematics are for the Marquis, some are labeled Thunder, Montery, etc. There is a lot of over lapping of applicability between the various models but the one thing that is missing from all of them is ANYTHING dealing with the rear start circuitry. If anyone has ANY information or thoughts on this please advise. The whole wiring of the rear start circuitry is confusing. For example, the rear start switch, the comp light switch, the rear oil pressure gauge which is not working, and the rear water temperature gauge which is also not working are all connected or wired together in some way. We have identified all of these wires but have not figured out how it all connects.
Now, I mentioned at the beginning that there was some good news. We finally did get it started, however, it is an on again, off again situation. Here is the time line and other details:
1. After replacing and cleaning the previously mentioned things for over 30 days and having no results, on Thursday 7/20 we started an attempt to identify and trace some wires. A the end of the day I turned the key as I usually do just to give it a try and low and behold the shift panel lit up and the engine started right up. I let it run for 10 minutes and I was able to drive a short distance and reposition the coach. Shut it off and restarted again as normal. All was well and I shut it off for the night.
2. 7/21 went out in the morning and turned the key and it started normally. Let it run for about 10 minutes and shut off. Did some more voltage checks, etc. and 3 hours later turned the key and the shift pad did not light and there was no cranking. Later in the afternoon we were again checking continuity/voltage from electrical bay to rear start switch and when I turned the key to accessory the shift panel lit up but the engine would not crank. I left the ignition switch on accessory and went to the rear start area and moved the switch to rear start and pushed the start button with no results. About 10 seconds later out of frustration I pushed the rear start button and the engine stated right up.
3. 7/22 Attempted to start from both front and back several times with no result. Transmission did not light up and engine did not crank.
4. 7/23 Attempted to start with negative results. I continued to test for voltage at rear start and wife turned ignition to accessory and the transmission pad lit up. I went up front and turned ignition to start and engine started normally. I shut engine off for a few minutes and then restarted normally. I did notice that the transmission light did blink momentarily and the "cat eyes displayed on the shift pad for 1 or 2 seconds and then went back to the normal display. The engine continued to run normally. I shut it off for a few minutes and then attempted to start with negative results. Shift pad did not light up and no crank.
5. 7/25 Went out this morning and attempted to start with negative results. No light in shift pad and no crank.
What all of this means I do not know. I do know that if the trans shift pad does not light up the engine will not start. Also that on one occasion the pad was lit up and it would not start from the front but on that occasion it did start from the back. I am leaning towards the problem being a bad/weak ground or frayed wire somewhere. Today we are tracing wires and checking continuity. Also I am replacing the relay in the fuse module tray although it may be O.K. Also I'm not sure about the factory label affixed to the battery bay door which lists the components of the fuse module tray as ECM Relay which is a 15 amp fuse, XSMN VIM 20 amp fuse, Service center 20 amp fuse, Event recorder 20 amp fuse, and an actual siemens relay labeled as ECMR. I assume the one labeled as "ECM Relay" is the 15 amp fuse and is not itself a relay but puts power to the ECM relay. After seeing the labeling on the electrical bay door I'm not sure what to make of this. One other thing, I would like to check the wiring to the back of the fuse module tray to check for corrosion but can't figure out how to access it. No screws are visible to take it apart.
This is a lot of information to digest but it is what it is. Not a simple problem to diagnose but am still hoping for a simple solution.
Any thoughts or ideas are welcome.
Tom
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Tom,
Symptoms sound like a connection or relay/CB that is intermittently failing. Since you know that the Allsion pad needs power for engine to start, consider focusing on it. If wire 265 is the Transmission VIM ign power relay, can you verify it has power in a non-start situation? If it does, then verify that power is coming into the VIM box.
Steve
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Steve,
One of the things I should have mentioned earlier is that during a couple of the successful starts mentioned above I did hear one or more of the relays in the electrical bay clicking quite a bit. I had not heard this before. Couldn't tell which one in particular was making the noise and it may have been more than one. This chattering continued for several seconds after the engine started and then everything quieted down and the engine continued to run. This happened 2-3 times. Also during the time when we were replacing some parts earlier I did notice that one of the relays in the electrical bay had a discolored connector as though the plastic connector cover had gotten quite hot at some time. The connection itself looked O.K. but the relay was replaced anyway. This relay has 4 terminals listed as condenser, condenser fan, ground, and wire #103 conds. The dash air is not functioning now and it hasn't been for a few months. Don't know if this is related or not but thought I would mention it.
Will be checking wiring on #201 and #202 and determine power delivery to VIM today.
Thanks,
Tom
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Tom, in beginning of problem you had motorhome at a Caterpillar Service shop. Cat tech
could not get any readout from data connector going to engine ECM and no start. You mention
Tech than remove data cable from the J-1 connection on engine ECM and would start and run with
caterpillar breakout box
Same time you mention on ECM pin 70 which is the power and believe pin 51 & 53 are the grounds.
I do have the same breakout box that tech started your engine which will aid in finding your
no start problem. Retracing wires from wiring harness of J-1 will send you into a cat relay off
J-1 wiring harness to motorhome harness. This has a relay that been problemic and replaced with service bulletin update. Wiring harness off J-1 on ECM connects to that relay within 4' of engine
To motorhome wiring harness. Dave Atherton Retired Cat Mechanic
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Tom,
The condenser relay should have no effect on the no start problem.
For future reference, the condenser fan relay hookup should be as follows. Relay terminal 30 or 87 should have a wire from one of the CBs (probably 7 or 9). I think this is the wire you listed as condenser. It should have 12v on it all the time if the CB is on the battery buss. The other terminal (30 or 87) should have a wire that runs to the fan itself (condenser fan). However, it may run to a terminal post in the elec bay labeled comp clutch as these are tied together in some applications. Terminal 85 and 86 control the coil of the relay and cause pin 30 and 87 to be linked. One of these terminals will be hooked to ground. The other should be connected to the trinary switch on the high pressure freon line (103 condenser??). When the switch closes, the relay trips and the fan should run.
Steve
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Steve,
Today, starting at CB22 in the electrical bay we traced wire #265 (labeled as Ignition Power to VIM Relay) to harness connector c-6 and up through the floor. From there it was all but impossible to see but with the aid of a tone generator found that the signal reappeared on two wires that came back into the electrical bay. One of the wires was labeled as #205/#446 engine brake out and the other was labeled as #204/#265 engine brake com. They both went into the transmission VIM on terminals D2 and E2 respectively. The two wires were checked for power at the end of the harness going to the VIM after disconnecting the plugs. Neither wire showed any power when the ignition was off, on accessory or start. Reconnecting the plug to the VIM showed the following results when measurements were taken inside the VIM from the "bridges" labeled from A through S. Ignition off showed nothing from wire #208 (power to reverse relay) on bridge B-1, and showed 12.5v when ignition was turned to accessory and start. Wire #232 (start) on bridge F-1 had 12.5 on start only and nothing on accessory. Wire #5A (batt power) on bridge J-1 showed 12.5v on off, accessory and start. Wire #5 (batt power) on bridge J-2 also showed 12.5v on off, accessory and start.
There are 14 wires that enter the VIM via the plug in question and they were all checked for power at the end of the harness going to the VIM after disconnecting the plugs. No power was shown on any of the wires.
Not sure what it means. Hope it's not too confusing. I'm pretty sure the above information is correct, but after a hard day of chasing wires,etc., the old brain can get a little fuzzy!
Also, thanks Dave for the info on the CAT relay. Will search for it soon. I believe that the CAT tech that worked on the coach said he accessed the engine ECU via the rear bedroom floor on the passenger side of the vehicle. Does that sound about right?
Thanks,
Tom
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Tom,
Am going to use email for responses. Easier to format, etc.
Steve
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Steve,
Thanks for the diagram. It was very helpful. I MAY have located the problem. The thermal circuit breaker located under CB22 seems to be the culprit. I had previously tested all of those breakers at different times and they tested good. After tracing wires #202, 233, and 265 yesterday via the tone generator and multi meter from CB22 it showed the wires were good from the right side of the ignition buss to the end of the wires. Then I tested the thermal circuit breaker under the buss itself and got no continuity. Eventually I was able to get a new 15 amp breaker and replaced it. Reconnected everything and went inside and turned the key and low and behold the shift pad lit up and the engine started. After fighting this no start problem for over 6 weeks it was a GREAT sound. I should be ecstatic and I am to some extent. Still not sure what caused the problem with the breaker initially. I'm pretty sure the breaker was an original so maybe it just gave up. I did notice something that did not seem right. After starting the engine I went back to the electrical bay and could hear the new breaker clicking. It would click about every 8-10 seconds and did this most all the time the engine was running. I put the meter on the breaker and it showed 12.7v and then when it clicked it showed 6.8v. The voltage continued toggling back and forth as the engine continued to run with no problems. I also took readings inside the VIM box and found that on terminal C (wire #202) and found that voltage toggled back and forth between 12.73 and 6.94. Terminal S also showed the same thing as well as fuse #2. Fuse # 1 showed 13v with no fluctuation. When the engine was stopped and turned to accessory everything showed 12.8v. Over the next hour I started and stopped the engine about 5 times (once from the rear start button) with no problems.
Do you think these reading are indicative of pending problems or is this normal?
Tom
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Tom,
Glad to hear that you found the source. Those breakers can just fail sometimes. When it's intermittent it's a bear to track them down. The CB clicking and voltage fluctuations is not normal and will cause problems. I'd first try switching the wires between CB-22 and another CB, say CB-27 (overhead fan). Both should be 15A breakers. You could switch it with one of the other ECU CBs but I wouldn't risk damaging an ECU just for a test. Once switched, go to ACC and turn on the fan for a load and see if CB-22 started clicking. If so, bad CB-22. If not, start the engine and see if CB-27 starts clicking. If so, there is a problem with the VIM or wiring to it.
Steve
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Steve,
I swapped the 3 wires (202 ignition ECU,233 ignition power air dryer, 265 ignition power VIM relay) on CB22 with the 1 wire (223) on CB 27 (overhead fan). Turned key to ACC and turned the fan on for the load. Fan operated O.K. and there was no clicking on CB22. Started the engine and CB27 started clicking just like before. Yesterday one of those three wires (#233) showed signal back to the air dryer when I attached the signal generator so I unplugged the dryer at the rear where it connects to the dryer just to check that out and it made no difference. Still got the clicking when the engine was started.
These are the results of the various readings:
1. Ignition switch off- Fuse #1=12.9v, Fuse #2=0, VIM terminal J=13.00v, VIM terminal R=13.0v
2. Ignition switch turned to ACC- Fuse #1=12.5v, Fuse #2=12.5v, VIM terminal B=12.5v, VIM terminal C=12.5v,
VIM terminal J=12.35v, VIM terminal P=11.41v, VIM terminal R=11.95v, VIM terminal S=12.25v.
3. Engine running- Fuse #1=12.98v continuously regardless of clicking, Fuse #2 toggled back and forth every 6-10 seconds between 12.74v and 6.9v, VIM terminal B=13.23v, VIM terminal C toggled between 12.73v and 6.9v, VIM terminal J= 13.12 continuously, VIM terminal P=12.29 continuously, VIM terminal R=13.1v continuously, VIM terminal S toggled between 6.96v and 12.74v,
4. CB22 also toggled between 6.96v and 12.79v on ACC and while engine was running.
I also noticed that I could feel all 6 relays inside the VIM click once each time as the VIM powers up. I have moved those 6 relays around and changed their position inside the VIM but have not noticed any change in the overall situation. I am assuming they are all good but I guess it's possible but not probable they are all bad.
Once again I'm not sure what these numbers mean, but at least the engine does start now. I started it 5 or 6 times today with no problems. I'm going to attempt to trace wire #265 (power to VIM relay) upwards towards where I lost it yesterday. It's a real "rats nest" up there with absolutely no room to work. Looked briefly at trying to remove the entire transmission console to provide better access but not sure if that is even possible.
Tom
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Tom,
Sounds like the ECU or VIM is causing the problem. Only thing I can think of is that a relay is toggling to cause the 12V to drop to 6v (and I don't know how it is doing it). To isolate the source try hooking the ECU wire up to CB27 (remove fan wire) and the VIM wire to CB22 and see which one clicks. Then switch them to ensure the problem stays with the wire/load. At least that will give you an idea where to look. Also, measure the 12V on the ignition buss when the clicking occurs to see if it is being affected.
Steve
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Tom,
It sounds to me like something is pulling a lot of current, heating a thermal breaker, and it cycles as it cools and then heats. If you feel around the VIM does it seem to be hot? In order to have a harness drop 6v on the way when in the on cycle, there should be some signs of heating. Some things that go bad that can cause that kind of current pull, dash air compressor clutch, dash air condenser fan, dash fan, blower speed control possibly, usually motors or clutches with wire windings that degrade. If you have a DC clamp on ammeter you may be able to check how much current is flowing and where it is going. As Steve pointed out, it may be possible that a VIM or ECM could pull this much current but it would seem unlikely that it would work if that much over current is being pulled by a computer.
Thermal breakers do fail and with use may go out of calibration or have poor contacts within them. If you have a sign of a bad one they are cheap enough to change. By design they do not tolerate many cycles of heating and cooling, they are not meant to do that kind of job long term.
I would be remiss if I did not compliment you on your dogged determination to solve this problem. Winston Churchill kind of spirit here, we will fight them in the trenches.... :-)
Later Ed
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Hello Ed,
I agree something has got to be pulling a lot of current. I am going to repeat some of the tests I did as described above just to be sure and also will check the VIM and anything else I can find for heating. I did previously check the temp of CB22 with a laser thermometer and upon starting the engine all thermal breakers were around 80 deg. After the breaker began cycling the temp rose to about 95 degrees on that one and seemed to level off. I am going to check wire #233 again today as it appears that wire goes to the air dryer as well as the alternator which was replaced a couple of months ago. Also going to be checking the condenser fan as I recently replaced a relay in the electrical bay which apparently controls the fan. It showed some overheating signs so I replaced it. I don't have a DC clamp yet but one may be in the works soon. I recently got a tone generator that has helped a lot tracing wires. I did recently buy 3 thermal breakers and replaced one on C B22 so far. I did take the old one apart and could see that the points on the contacts showed definite signs of pitting. I have no idea as to how long it might have been cycling.
Also, in some PM mails to Steve I mentioned that yesterday the engine failed to shut down. The first time I switched ignition back to ACC and then to off and it shut down. About 10 minutes later it failed to shut down again This time it took 2 tries to the off position and it finally shut down. I am a little hesitant to start it today, so here is the question; Do you know of a way to reliably shut the engine down if this happens again and the ignition doesn't work?
Thanks for the Winston Churchill reference. We are definitely DEEP, DEEP into the trenches!
Thanks,
Tom
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Tom,
Before you jump to another problem, consider fixing the one you've been working on. You've verified that wire 233 is the wire that causes the CB overload. It goes from the CB through the firewall connector C4-2 to the chassis connector C51-31 and then to the air dryer connector C60-A. There is no indication on any print of it going to the alternator so if it does on your coach, it is probably a mis-wire. In any case, remove the connector at the air dryer and verify that the CB overload stops. If so, you probably need to replace the dryer. If not there is probably a short or resistive path to ground on wire 233 between the CB and C60 or a mis-wire.
Steve
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Steve,
Today we moved #233 to CB27 and removed the wire to condenser fan so it was not hooked up. #233 is now the only wire on CB27. The other two wires were left on CB22. Also disconnected the air dryer in the rear. I had tried that a few days ago and it made no difference in the clicking but thought I would try it again. The results were that wire #233 on CB27 was the only one that clicked and toggled between 12.9v and 6.9v just like on the previous day. Inside the VIM the change was that fuse #2 showed continuous 12.9v and did not toggle as it did when #202,#265,and #233 were all connected to CB22. I think if may be safe to assume that somewhere in the path that #233 takes is where the root of the problem lies. Will continue to trace it all the way.
In regards to the alternator: The schematics and diagrams that I downloaded from the BAC site shows #233 as a terminating point at the alternator and S1. I believe this diagram was on page 14 of one of downloads, possibly the #3 download for the Marquis. I will try to locate it for sure and advise. In tracing the wire today with the signal
generator it did show a signal at the alternator and also at the dryer.
Also, as I feared, after doing the testing with the engine running today I attempted to shut it down after turning ignition to off the engine did not shut down. I turned the key back and forth several times with no results. It ran for about 5 minutes while I was trying to figure out what to do. I turned the ignition to off a couple of times and still no stop. I then turned the ignition to start for a split second and then back to off the it did shut down. I,m sure the starter did not like that but at least it stopped. Not a good feeling. I fully agree to try to solve one problem before starting on another but in this case it is impossible. The only way to check the breaker cycling is with the engine running.
Tom
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Tom,
I'll check more re 233 path also and see if I can find that print.
As for shutdown, I "think" that if you remove power from the engine ECU line it will shut down.
Steve
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Tom,
Found the dwgs. The wiring is shown in part 4 of the Marquis dwgs on ppgs 5 &7 of 10 and in the 2003 Patriot dwgs on ppgs 14 & 15 of 86. Both are for Thunder models.
Wire 233 goes from C51-31 to S1 at the alternator and then to C60-A the air dryer. Would seem that the alternator is a good candidate for the source of the overload.
I'd also change the wires to CBs to agree with the diagram in your the electrical bay. One of your earlier posts noted that CB 22 was labelled for Service Brd, Xsmn, ECU and VMS2 but had 265 Ign Pwr VIM relay, 202 Ign ECU, and 233 IGn pwr on it. Which CB does your diagram show Ign Pwr going to? Is it possibly a 20a breaker??
Steve
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You also want to measure the DC current draw on the feeds.
Interesting that you see 6V with the breaker open - unless some other circuit is feeding current there the voltage with breaker open should be zero.
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Steve,
I agree, I think it is getting down to a bad alternator or improperly wired alternator. In my original post I started by describing a no shut off situation followed by a no start situation several days later and then describing what happened from there. I am now thinking back to the trip that preceded that trip. About a week before that I drove from Texas to Indiana and along the way in Missouri the alternator went out and had to have it replaced. The original Leece-Neville was replaced with Road Choice ALT24H at a Volvo truck dealership. Coach seemed to run O.K. on the rest of the trip but now I am wondering if that might be related. Haven't had time to check on the new alternator but am wondering if it is compatible with the duvac requirement of my coach or if it might not have been installed correctly.
In regards to the wiring in the electrical bay I am pretty sure it is still the way it was when it came from the factory. We are the second owners of the coach and I am sure the previous owner would not have altered it. We have operated the coach for over 12 years and never had any kind of electrical problems so I am pretty sure the basic wiring is correct but just just doesn't agree with the placard information. I believe the wrong placard (sticker) was applied before it left the factory. I noticed that the placard is labeled as Patriot and not Thunder. I'll try to send you a picture of the placard. Our layout is different in a couple of ways in that the placard shows 9 relays and we have 10. the ground terminals and TB layouts are also different as well a the labeling not matching the wire numbering.
In regards to which CB does the diagram show Ign Pwr going to is a little hard to determine. CB21 just says ECU and CB22 says Service board,xsmn, ECU, and VMS2. I don't think it goes to a 20amp because there are only 2 breakers 20amps or more and they are for CB25 headlights (30amps) and CB 29 AC (20amps).
Took some voltage readings at the alternator yesterday. The 3 terminals on the back of the alternator are listed as I (possibly 1), R, and B+. Here are the results after taking the readings several times: With the knife cut off switch located just in front of the electrical bay solenoid disengaged terminal R= 0amps, terminal I=12.53 and terminal B+=1.73amps. With the ignition turned to ACC, R=12.13amps, I=12.28, and B+=11.49amps. Haven't been able to take readings with the engine running but may be able to do that today.
Another interesting thing is that when testing continuity from the start of wire #233 to the alternator I was able to get consistent continuity on terminal R but on terminal I would occasionally get one beep on the meter and then nothing. Seemed really strange. Don't know if it could be my meter or something else.
Tom
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Tom,
Are you sure of the Road Choice part #? Their web site doesn't show any such animal.
Steve
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Steve,
This is the part number as listed on my bill by the Volvo truck dealer that installed. RC-ALT24H. Price was $198.63 plus $550 installation. Said they had a hard time getting the pulley off the old one. When your on the road traveling and have to get somewhere they GOTCHA. I tried to look it up on the Road Choice site also and couldn't find it. I did find it on a different truck parts website, but couldn't get much additional information other than it is a hinge mount rated at 160 amps. They listed a Delco 8600310 as a cross reference.
Tom
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Think it is equivalent to their 8329 which is also a 160A unit, but not sure.
Steve
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To All,
SUCCESS! SUCCESS! I THINK! After switching the I and R leads on the alternator and taking more readings just to make sure I gave it a try. Engine started right up and no clicking. Ran it for about 5 minutes and turned key to stop and it shut as it should. I'm going to let her rest for the night. After 49 days of non stop digging, pushing, pulling and yes , a few choice words I think we finally got to the root of the problem. Will do more exploring , etc, to make sure there are not any more gremlins lurking in there. After getting false hope several times we are not ecstatic yet. After this amount of time it will take some time to get back to normal thinking. We are not in a total celebration mode yet just in case but are getting close. Thanks to all and I will post more when/if everything continues to check out.
Tom
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To All,
SUCCESS! SUCCESS! After getting false hope several times we are not ecstatic yet. We are not in a total celebration mode yet just in case but are getting close.
Looking forward to your post when it's affirmed. I think SUCCESS! SUCCESS! is pretty ecstatic! ;D
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Tom,
A big congratulations! This scenario makes sense, the errant connection at the alternator was pulling excess current and tripping and cycling the thermal breaker. Apparently this errant wiring was also back feeding voltage to the output side of key switch circuit wiring, that kept the ignition on at a marginal voltage level, so it would not repeatedly shut down when you turned the key off.
There is a lesson here about retracing steps of electrical work that has been done recently by someone else, if something isn't right. Although you would like to think that you would not have to, verifying that the wiring is correct, and the electrical connections are tight after someone works on your coach is probably a good practice if you have the skills. It is especially easy for a tech to mix up wiring when you are not using an exact replacement part and another alternator in this case may have differing terminal placement or labeling.
Later Ed
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Tom, great job in staying with problem. The bad thing about all of this, you paid big dollars to
inherent a problem and that is becoming all to common today. Again the BAC forum is a real
Important tool in assisting members. Steve Huber has spent countless hour digging for information.
Problem today as motorhomes getting age on them, like kind parts or one size will work for all
but will not work correct and tech mechanic's are not experienced to see problem at hand. The
good Tom, that has came from all of this ( you have a better understanding about your Engine
And motorhome chassis). Dave Atherton Retired Cat Mechanic
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Tom
Glad you are running (and stopping) again!
Steve
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Great job Tom way to stick with it.
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Wow Tom what a success! At least we'll call it a success at this point and hope it stays that way. As I have the same coach as you and will probably be replacing an alternator in the near future your detailed troubleshooting was invaluable to me as well as others .. Thank you!!
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Well, it has been six days since we called this a success and I think it still holds! Coach has started and stopped without fail on several occasions. However, I felt that the batteries were still not charging as they should so I removed the alternator and had it checked. Sure enough it was only putting out 8 amps. Dropped it off at a repair facility at 5 pm yesterday and today at 10 am they called and said it was ready to be picked up. They replaced the regulator/diode module. I am getting ready to reinstall and want to make absolutely sure I get it hooked up correctly. I have 5 wires to connect to the alternator. The ground and the large positive output cable are pretty obvious as to where they are to be attached. It's the other 3 white wires that I am concerned with. The following readings were taken at the end of the wire when none of the wires were attached to the alternator. #1 wire showed 12.51v with ignition off and 12.38v with switch set to ACC. Wire #2 showed 0v in off position and 12.28v on ACC. Wire # 3 showed 0v with ignition off and 0v with ignition on ACC. On the back of the alternator there are 3 terminals (not including the ground) R, I, and B+. The large positive cable I am pretty sure attaches to the B+ terminal. Previously I had taken readings at the alternator terminals with the wires attached and of course the reading were different than the above readings. Based on these readings can anyone advise with certainty on which alternator terminals the other 3 white wires attach to the alternator? Also, once I get the alternator reinstalled what should the approximate readings be at the 3 terminals with the engine running?
Once again, thanks to all who have responded throughout this saga and offered their helpful suggestions, especially to Steve who I know must have spent numerous hours on this and also to Ed for his thoughtful input. I started with almost zero knowledge on the subject and have gained at least a basic understanding of a lot of systems on the coach. As was noted above some of the placards installed on our coach were not the correct ones. This caused a lot of delays. Anyone else with this year and model who is running into problems of this nature feel free to contact me and discuss if necessary.
Tom
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To late now, but always tag wires or take pics before taking the piece apart, smart phone is a powerful tool.
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I do have pictures and the wires were tagged before I removed the faulty alternator. As I mentioned in a previous post, I believe the problem occurred when the repair facility installed the new alternator and they did not connect the wires properly. Yes, it would have been nice to have pictures before they replaced it, but if you have ever broken down on the road things don't always go as you would like. The question now is what is the proper placement of the wires? I want to double check with anyone that has a similar coach set up (i.e. echo charger) with a properly connected alternator. I believe I now have it connected properly. Just want to double check. Don't want to have it repaired again.
My readings which were taken today with the engine running was R terminal=10.57v, I terminal=12.20v, and B+ terminal=12.94.
Tom
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Tom - without any warning last year I had the same problem. No lights on your shift pad & the engine can't tell if the tranny is in neutral - so no start! I took the shift pad & the ECU/M? to a Allison dealer to test. Turns out my shift pad was defective. Allison sells a new shift pad replacement for mine at about $950 which is guaranteed for only 90 days. I found a company in Conn. via the Internet which sells rebuilt units for about $350 & they guarantee them for 1 year. The shift pad has to be programmed to your engine VIN #. I supplied the VIB # to the folks in Conn. Took 3 days to get to me while I was on the road. You just have to return the shift pad unit or pay a core charge.
Bart from VA
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Tom,
Wire 233 should go to the I (ING) terminal. The B+ terminal should be connected to battery voltage. This leaves terminal R should be alt out for the 3rd wire. Verify this is how you had it connected before you removed the alternator.
Steve
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Steve,
To clarify things, wire 233 comes from ignition side of CB and goes go to the I terminal. The B+ terminal is connected to battery voltage via a large cable to the battery isolater. Terminal R "alternator out" would be wire #450 according to the schematic). I have not yet been able to trace this wire to its' termination.
What I have found out is that the original alternator was a Leece-Neville A0012824LC. That alternator has an additional terminal labeled "S". The alternator that the repair facility used as a replacement does not have an "S" sense terminal. The Alternator they used is a Road Choice ALT24H (160 amps). I have not been able to find much information on this exact unit, however it is a clone of a Delco-Remy 8600310 (160 amps) which is a non "S" terminal model. This is why I have a total of 5 wires and only 4 terminals. As I mentioned in my post of Aug. 9 I know where the positive and negative wires attach, but it is the other three white that are a concern. So I guess the question is where do the wires go when you are converting from an alternator with an "S" terminal to one that does not have that feature?
I did get on a Delco site and apparently this can be done. They explain how to hook up an alternator with a sense terminal and it appears as though the Beaver set up is exactly like this including the use of a 5 amp blade type fuse all of which I have. They also stated that " If installing a non-Remote Sense alternator in a vehicle that has a Remote sense line, disconnect and secure the wire from the battery. Only connect the Remote Sense line to the Remote Sense terminal. The "R" and "I" terminals are not the Remote Sense Terminal!". They also stated that the only downside is that with out the sense feature the batteries will get about 1/2 amp less charge initially and is usually only important if the vehicle engine is making frequent starts and stops.
Has anyone done this and have there been any downsides. I really don't feel like buying another alternator unless I absolutely have to.
Thanks,
Tom
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I failed to mention I traced the 1A (according to the schematic) white wire,which I believe is the "Sense" wire to the starter solenoid, which was "hot" all the time.
Tom
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Tom,
I'm out of ideas. Wire 450 already has a 5a fuse and diode in line per the dwgs. If we knew the wire #s on all 5 wires it would help. There is 450, 233, 1A?, ??, ??.
Consider calling Leece Neville, BCS or Road Choice for advice once you have wire #s and labels of where they are supposed to go according to dwgs.
You said you had switched a couple of wires and things appeared to be working. If it starts, stops, and charges. what problem are you trying to solve?
Steve
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The 5 wires are identified on the dwgs as #233 (which I have physically identified and traced from the ignition side of the CB to the alternator), #1A (which I believe is the "sense" wire and measurement showed it to be hot as it should be all the time) I have traced it to the starter solenoid and it attaches to the large solenoid post along with the large positive cable which goes to the solenoid. Concerning the #450 wire: ( the one with the 5 amp fuse and diode in the line) I am still working on it. I think I have identified it with a signal generator but haven't been able to actually see the numbers on the wire and have not yet been able to determine where it terminates yet. The last two wires do not have numbers on them but it is obvious they are the alternator ground cable which terminates on the left side of the engine connected to a ground stud along with some other ground wires. The last of the 5 wires from the alternator terminals is the large positive cable which does not have a number on it but it goes to the battery isolater.
The problem I am trying to solve is this: When I first switched the wires on the alternator the engine started and stopped normally. The readings I got when the engine was running was- R terminal 10.57v, I terminal 12.20v, B+ terminal 12.94. Are these readings within acceptable limits? It would seem to me that upon starting there should be higher initial readings on some of these terminals. The readings stayed the same regardless of the engine RPM. As I remember from earlier times before I had any problems that the ammeter silverleaf and CMP would initially show in the low 13v. The ammeter, silversleaf and CMP all showed higher readings than what I have shown above.
Today, after switching the wires as described previously and taping off the sense wire as described in the Delco instructions (remembering that their instructions are for converting from a "sense" equipped alternator to a "none sense" equipped alternator which is what I am doing since the repair facility installed a "none sense" equipped alternator) these are the readings I obtained while the engine was running: R terminal 7v, I terminal 13.9, B+ terminal 14.08. Obviously these readings are significantly different that the above readings. In addition the engine would not shut down from the key switch up front. It did stop when I used the front/kill/rear start switch in the rear service bay.
It gets down to the question of which of the above two set ups is correct or is there a 3rd option?
The first option seems two be putting out too low of an initial charge to the batteries and the second causes a shutdown problem.
Tom
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Tom,
The sense wire you are referring to could go to the tachometer on some coaches that use the alternator as a pulse generator to provide an rpm related signal. The first set up of the alternator using sense mode, the output is to low. About 13.8V to 14.1V would be appropriate for an alternator as long as it is handling the current load and is not derating itself based on high current output as part of the protection circuitry. Obviously you do not have that problem in either sense mode.
The taped off sense wire should have no bearing here given it is just a straight B+ wire from the starter terminal and does not lead to any component that has a toggled circuit to affect the running of the engine.
I think I would see between the two alternator set ups (sensed and non sensed) what the voltage level is with the ignition switch on and off at the main electrical bay ignition buss and the small wire input to the solenoid that comes from the key switch. I am not sure how the shut down input is derived and where it goes but I think it must be some wire that is tied to the ignition buss. My thought is there must be some difference in how this toggling of voltage is taking place on that wire.
The other thought is what is different about the rear start on off circuit? What wire input is getting toggled with that switch, what are the voltage levels on that input wire using the rear switch vs the front switch. Ultimately the same input wire to a shut off circuit needs to be toggled whether you use the front vs back switching.
If you find that you can get this to work from the back only and you find that the front ignition buss solenoid is working with the front key switch (toggles to 0V) but the engine continues to run then you could run a wire from the front ignition buss to the rear start switch and add a Bosch style relay in parallel with the rear ignition switch and fire the coil with the wire from the front buss to open NC or NO contacts to mimic the current switch. This option is a bit of a pain but may be less work in the long run... Hope this helps.
Later Ed
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Tom, Ed,
The tach gets its signal from the ECM so not clear what would be hooked to the "R" terminal of the alternator as I think it is a pulsed signal from the stater.
Steve
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Tom,
Not sure if you noticed this in prints. The 450 wire (5a fuse and diode) is only shown going to alternator on coaches w/o a service center. Coaches with a service center only have wires 233 and 1A (ign and sense) running to alternator.
Although I can't find it on the prints, I'm wondering if 450 powers the Racor prime system???
Steve
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Steve,
Yes, I did notice this on the prints but this does not correspond to the set up on my coach. The 450 wire, which I have identified with the 5 amp fuses and diode, does go to the alternator but I do have a rear service center ??? Also contrary to the prints I have 233. 450, and 1A running to the alternator. I just have to assume that they changed the set up sometime during the manufacturing process. Interesting thought on Racor prime system. In trying to trace the wires from that system I could only find a packet of perhaps 3-4 wires incased in a fairly heavy plastic sheath. I didn't get in to that. It may now be a moot point which I will explain shortly.
Ed,
I was just about to start the process you outlined in your last post and thought I would call BCS to see if they could add any information. In talking to Ken Carpenter he advised that a great many inquires he gets on alternator problems occur after changing brands from the original Leece-Neville. He also advised that he could not describe the routing of the wires that might be involved but said that most of the time when the owners went back to the original their problems disappeared. The following day I had occasion to be in a town that had couple of automotive electrical shops that service and sell alternators. Thought I would stop in just to check the price on a new Leece-Neville in the event that the next series of tests and the last ones that I was going to try, the ones that you recommended didn't solve the problem I would probably bite the bullet and replace the alternator (ugh!!). In talking to the counter man ( I had never been to this place before) and explaining the numerous problems I was encountering, including trying to hook up a "non sense" alternator to a coach that previously had a "sense" system he advised that if it were himself he would install a diode right before the "I" terminal on the alternator. He felt that that since that output numbers I was getting was good that the diode might very well solve the problem of the engine not shutting down. Then he "GAVE" me the diode and wished me an early Merry Christmas. I went home and wired it in as he suggested. The engine started right up and shut down as it should. I tried it several times and everything was fine. I am REALLY hoping I can finally put this thing to bed!
Ed, I think you were very close to nailing this one down. I remember one of your other posts suggested feed back going back up to the ignition might be causing the problem. Thanks for all the help and to all others who have contributed.
P.S. One other thing for those of you who may be having parking brake problems with the disc system, when I was talking to BCS I ordered a new parking brake pad since one of mine has worn down again almost to the metal, the parts man mentioned that they have a retro kit which consists of 2 springs which will keep the pads separated and should eliminate many of the wear problems. I did not know this was available. Not sure if this is a DIY project or not but Ken is sending installation and adjustment instructions along with the pad.
Tom
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Is it charging as it should?
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Yes, it is charging now. The diode is installed with the silver band facing toward the alternator and the output did not change from what it was before the diode was installed. The only effect it seemed to have is that it solved the no shut down problem. I have checked it three different times with the engine running and the average readings were: B+ terminal 14.06v, I terminal 13.25v, and R terminal 7.03v.
Tom
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Tom,
You never know where the solution will come from.... thanks to Ken and the mystery alternator shop counter guy.
I thought back feeding was involved but I did not know exactly which terminal was involved or how it might be fixed. Good for you.....You get the Beaver Perseverance Award winner for 2017 :-)
In these kind of problems sometimes it can be just voltage noise coming off a terminal like that which degrades the on off voltage levels at the ECU terminal so the noise goes above the turn off voltage sense threshold. Alternators are notorious for putting out voltage noise. With audio in radios many times you can hear a whine related to RPM and you need to add suppression electronics or move the power lead to the battery terminal. The diode is probably blocking pulse noise from getting on that wire.
My suggestion would be to create a new post titled "Engine Non Shut Down Using a Delco Non Sense Wire Alternator As A Leece Neville Replacement" or whatever title best fits getting future hits on this issue. Document the symptom, the terminal, the diode arrangement, even a photo of the alternator with the diode if possible. I think this is something others may face on the road when a Leece Neville is not available.
Hope you can go have some fun in that Patriot now :-)
Later Ed