No Crank. C12 Cat

[Brian Buchanan]

Here is my dilemma today, Have not started the coach since early May, at that time every thing seemed to be fine. Shortly after parking it at our summer location the rear leveling switch panel shorted out (RVA system) and the electric hydraulic pump was running. I disconnected the rear RVA control panel and when diagnosing found several corroded spots on the printed circuit board, with the rear control disconnected the front unit operated fine so I left the rear disconnected while I try to source a new switch panel this fall. And I don't remember trying to start the coach after that incident. This week as we are starting to prepare for our fall escape south I decided it was overdue to be started but the motor will not crank, the batteries are 12.6 volts, the ignition switch is operating and energising the (start wire) when in the crank position. I'm getting all the warning lamps, when the key is in the run position but nothing in the crank position, I'm not hearing any starter solenoid. I do not have a wiring schematic so I'm hoping someone can help he trace the "start" wire from the ignition switch, the transmission is indicating neutral, but from what I have read it may have a starter relay before the starter solenoid.

I have not triggered the starter solenoid to confirm the starter operation yet, as I have never had any previous issues, any ideas would be greatly appreciated.

[David T. Richelderfer]

You might try removing the battery leads and cleaning the leads and posts.  Also, when turning the key to start the engine, try pressing the battery boost switch.  Also, you could remove the leads on the starter to clean them too.

From there, perhaps the technical guys can pitch in with some ideas.

[Carl Boger]

Brian,

By will not crank do you mean it is turning over but not start, or its simply not turning over at all.
Do you have dash lights?

I have had my coach not turn over at all, and the cure was to disconnect the front wiring harness plug in the front electrical bay under the drivers foot well area.  Clean the Pins really well with electrical cleaner and a brass brush and wire welding tip cleaners.  After plugging it back together it fired right up.  I followed up with some dielectric grease around the case and a zip tie to keep the plug halves tightly together. 

Hopefully your fix is this simple.

[Eric Maclean Co-Admin]

Brian
The wiring diagrams should be in the coach assist library here on the forum ( follow the blue link at the top right of this page )
That era ( Magnum chassis)  should have a primary starter solenoid located in the back left rear corner of the battery bay.
First  check the rear start switch controls at the service bay as they can be problematic ( as the rear of them is exposed to weather and road grim )
Both the ECM relay power and the start signal pass through the rear start switches and if the switch is in the wrong position or goes bad you will have a no crank situation from the front start position.

Eric

[Keith Moffett Co-Admin]

Not sure of your starting circuit so I’ll leave that to others.  The RVA company is now part of Brazel’s group in Centralia Wa. (800) 417-4559.
Good luck.