03 Marquis no start

[william harrison]

 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
 

[David T. Richelderfer]

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).

[Keith Moffett]

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!

[william harrison]

 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.

[Keith Moffett]

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.

[Dave Atherton]

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

[william harrison]

 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?

[David T. Richelderfer]

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.

[Dave Atherton]

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

[william harrison]

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)?

[Dave Atherton]

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

[william harrison]

 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.

[Dave Atherton]

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

[william harrison]

 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.

[william harrison]

 Anybody know what model Allison they used in the 03 Beaver?