Beaver Patriot Thunder Won't Start

[Steve Huber Co-Admin]

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

[Tom Blad]

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

 

[Steve Huber Co-Admin]

Tom,
Am going to use email for responses. Easier to format, etc.
Steve

[Tom Blad]

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

[Steve Huber Co-Admin]

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

[Tom Blad]

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



     

[Steve Huber Co-Admin]

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

[Edward Buker]

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

[Tom Blad]

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

[Steve Huber Co-Admin]

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

[Tom Blad]

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





 

[Steve Huber Co-Admin]

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

[Steve Huber Co-Admin]

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

[Neal Strickberger]

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.

[Tom Blad]

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