BAC Forum
General Boards => Technical Support => Topic started by: william harrison on February 14, 2016, 09:06:46 PM
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My batteries are at full charge, power goes to the ignition switch and out the starter contact; the
engine/ignition solenoid in the driver's side bay pulls in when the ignition switch is turned on, and all circuits are powered through their respective breakers. The dash lights up, the transmission is in neutral (I tried changing the selector to d then back to neutral). Had my son listen at the rear of the coach and he heard no solenoid pulling in when I turned the switch to start position. The Bendix will pull in if I jumper it.
Monaco told me there was another solenoid in the system (on the frame rail near the starter) that is the final link
in the starter circuit but the only other one nearby is on the roof of the house battery compartment and can only be
accessed by removing the house batteries. I have no schematics and do not know the location of critical elements in the
circuit.
Any help will be greatly appreciated.
william (chuck) harrison
Akron.Oh
03 Marquis Ruby
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The large blade fuses are all good? Mine are located behind a door above the coach batteries (door size is about 5" to 6" high by 12" to 15" long; a turn latch on its left and hinged on its right).
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Does the starter turn the motor when you jumper it? You said the starter engages when jumped.
Friends of ours had the C9. Their starter did much the same thing. The motor wouldnt turn but when the ign. Key was held on and the harmonic had just a little extra push by hand, the motor started.
The up shot when the starter got pulled out was dirty contacts through out!
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Blade fuses are all good and I did not try cranking the engine. Since the bendix did not pull in using the ignition key I was sure
the problem was further back up the circuit.
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William
If the blow by hose has not been moved, it likely dumps out right behind the starter. The oil residue it leaves collects dirt in the starter. This could account for a bendix that hangs up.
Just an idea.
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William Harrison, I have with the no start with Cat or cummins with Monaco , the
Neutral safety switch female socket had lost ground to neutral safety switch relay.
The male probes sticking out of relay the bottom left corner is the ground. I had to
connect a jumper wire to ground probe male that is inserted into the female socket
than find a good ground ( engine would start ) In order to shut engine off remove
ground clip. There is also in the start circuit ( one 10 amp, and( 2) 7.5 amp inline fuse
that are located in battery area for chassis power. Note: these were a temp repair
to get motorhomes up and going at rest area and Walmart so they can get into service
Repair shop. Maybe this will help. Dave Atherton Retired Cat Mechanic
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Talked to Bend RV Repair and Jeff told me to check the Allison transmission control box where the neutral safety relay is located, any ideas where
this is located?
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In my coach there is a black box located under the keypad that has a couple fuses and other electrical stuff enclosed within it. To access the box you have to go through the console's side-cover panel by removing a couple screws. This side-cover panel would be located lower than and beside your left thigh/knee as you sit in the pilot's seat. When you find the black box, it opens like a clam-shell by loosening several screws around its outside edge. I have no idea if the black box is the "control box" you are looking for, but it's worth a look.
When I had my electrical issues 2 or 3 years ago, one of the fuses in the black box had blown which would not allow the Allison to report neutral to the engine... which must be reported before the engine is allowed to start.
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Gentleman, the box in question holds 10 relays in 2 rows. There is 2 (10 ) amp fuse that
are located at end of each row of relays. This is where the neutral start relay is located
In my above post I was talking about. Have found this box in the battery compartment
area. Have found this relay box up front right next to foot feed on some brands behind
Cabinet in center. Dave Atherton Retired Cat Mechanic
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Gentleman, the box in question holds 10 relays in 2 rows. There is 2 (10 ) amp fuse that
are located at end of each row of relays. This is where the neutral start relay is located
In my above post I was talking about. Have found this box in the battery compartment
area. Have found this relay box up front right next to foot feed on some brands behind
Cabinet in center. Dave Atherton Retired Cat Mechanic
Is there anything other than the neutral safety switch/relay that would prevent starting
(assuming the start relay checks out good)?
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Mr. Harrison, one thing to try to narrow problem down. Take a jumper wire and connect
battery postive connection to starter solenoid, than the other end of wire to the little terminal
on starter solenoid. With starter switch in start touch the little wire terminal with the jumper
wire. This will energize starter solenoid and motor should spin and start. If nothing happens
real strong possible replacement. Not sure where problem is ( starter is dead and will not
Turn engine over or engine turns over but no smoke or start ) getting back into your problem
by taking the starter away first than go different direction. Can you give your engine S/N number
this will help. Dave Atherton Retired Cat mechanic
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I give hearty thanks to all who have tried to help. Unfortunately I have to wait for some help
in analyzing the problem and have a small window in which to do this. If someone
could provide me with an ecm wiring diagram for the c-6 it would help if I can't find another cause.
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Mr Harris, are you close by to a cat Dealer where a field service Mechanic can come out
And connect Cat ET into your engine ECM and tell you what is happening ? Wish I was close
To you and I could help you out. It is not a good idea to start messing in any way
With the engine ECM and if you do just remove the J-1 data cable but I would suggest not to.
The engine ECM has several different voltage at this 70 pin ECM connection.
Dave Atherton Retired Cat Mechanic
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I finally got some help yesterday and was able to get the engine started. Also replaced the start solenoid
but that was not the problem. Bench testing showed that the start solenoid operates fine.
Also checked the start input to the solenoid (disconnected from the solenoid) and got no signal.
Looks like it is down to the neutral safety switch or the relay, I don't see anything else in the start circuit that
could interrupt the signal path.
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Anybody know what model Allison they used in the 03 Beaver?
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On my 03 Marquis Its a Allison 4000MH and just for extra info the Trans ECU is a WT3ECU910A Off my Spec sheet in the Bath Medicine cabinet door
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I disconnected the signal wire from the start relay and using a signal sniffer I traced it to the bundle of wires inside the shift column, then separately
traced the start wire from the ignition switch, no connection (as expected)
one wire is labeled 232 and the other 232a. I could find no connection between either wire and the Allison shift control box where I was told the neutral safety relay is located. I have installed a rear start pushbutton
but still want to solve the original problem.
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William,
When you say you disconnected the wire from the start relay, do you mean the starter solenoid ? When you say you found the other end in the bundle in the shift column, what exactly are you referring to? Are you saying that you have continuity from the starter solenoid up to the touch panel area where the Allison control panel is located?
Later Ed
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There is a solenoid in the coach battery compartment that connects to the starter Bendix. The solenoid is energized by
a "start" signal that comes from a wire located in a bundle of wires that pass through the "shifter column" where the touch panel
shift control is located. It does not connect to the ignition switch. Supposedly the "start signal" comes from a connection made
between the ignition start wire via the neutral safety relay in the vim. I could not find a connection between the start
signal and the vim.
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William,
I think I understand better....so you know that the relay in the rear works going to the starter Bendix and you have temporarily created a start button back there. You know that you have a path from the shift panel area to the rear relay.
It would seem the next steps are to apply 12 V to the wire that comes into the shift panel area and convince yourself that the wiring path from the shift panel area to the Bendix through the relay works. if it does then I think that you need to next verify what wire at the ignition switch is energized in the "crank" position and trace where that wire goes and verify that it is applying 12V where it is terminated.
I am not sure if you have contacted Monaco and or BCS to see where this relay is that enables the start sequence based on the shift pad gear position. It would be logical that it is in the shift pad area but you never know for sure. So basically verify the operation from the shift pad area back to the starter and then work from the ignition switch back to the shift pad area tracing the wire code and voltage.
Later Ed
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William,
Ignition Power comes from the shifter panel via wire #250. You can verify if it has power at CB27 in the electrical bay beneath the driver's seat.
If you haven't already, you may want to take a look at the Marquis elec. wiring diagrams in the Coach Assist section of the Members Only board.
Steve
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William,
I did some checking of the 03 Marquis wiring diagrams. Wires 232 and 232A enter the VIM via C42 pins 2&3 respectively. Both are labeled “Start” in the diagrams. 232 goes to the ignition key solenoid and ties into the Firewall Harness Connector C1 Pin 2 and runs back to pin 2 on C51, the Engine harness interface. From C51, 232 goes directly to the starter solenoid.
I was unable to trace 232A any farther but suspect it tells the VIM when the engine has started.
I found no fuses in the circuit, which leads me to suspect that one of the 2(?) fuses in the shifter console may be the culprit. See the below referenced thread for a description of the fuse locations.
This thread describes a problem similar to yours. David did a lot of troubleshooting but located all the fuses.
http://beaveramb.org/forum/index.php/topic,2701.msg20869.html#msg20869
Hope this helps some.
Steve
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I noted that I replaced the "start" solenoid with an aftermarket one and found that the original one was good.
At that time the shift panel lit up and I could start it using a jumper on the start solenoid. In the process of
re-installing the start solenoid I accidentally grounded the hot side of the solenoid momentarily and now the
shift panel is dark. Yeah, I know I should have disconnected the battery lead.
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William,
It will not start if the shift panel is not powered. Check the fuses under the panel in the driver's console.
Steve
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It does start Steve. Where is the fuse panel again? I see what looks like a cutout on top of the dashboard
but no fuses visible under the dash.
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I can start it only by using the rear start switch I installed. Just saw a schematic of the fuse and relay block located in the chassis battery compartment and it shows an output to the vim. Is this where vim power comes from?
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William,
The fuse I'm referring to is an automotive type fuse located under the transmission gear selector pad just to the left of the driver. You'll have to remove the side panel(s) to gain access.
Steve
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I still have a blank shifter panel. I checked the fuses inside the VIM and they are ok.
I left the start signal and ground open on the start solenoid and checked
for secondary fuses and found none except for the fuse tray on the wall of the battery box where a beaver schematic shows the source of a wire labeled VIM
power but does not indicate which fuse. I suspect these are thermal activated
fuses. On the circuit board inside the VIM I have 12v on pins 6,7,8 and 16
reading from top to bottom.
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William,
Out of ideas as I don't have a schematic of the VIM itself. If you haven't yet, suggest you download and reference the "2003 Patriot Thunder Schematics Marquis, and other models 98 – 2003 Mixed". It's located in the Members Only Coach Assist section and has the best quality prints I could locate. You may also want to call BCS to see if they have a wiring diagram of the VIM itself or any ideas.
Good Luck, Steve
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Everything is fixed. Problem(s) turned out to be located in the fuse panel in the engine battery compartment. A corroded contact on the ecm relay and a blown 20amp fuse that powers the vim. Thanks to all who responded.
Ps I purchases a wtec3 Allison manual and will make it available to all if I
can figure out how to do so.
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William,
Good for you...it has been a long road to get to this cure. Great sleuthing and perseverance on your part. Any chance that you could take a photo of the relay and fuse location involved and post it. It might save the rest of us a long search if we had a similar issue. It may be mounted with others but you could use words to point us to the culprit.
Later Ed
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William,
Glad you found it!
Steve