Another 12V Dead Issue.....

[KenJim]

Last evening while in Quartzsite I turned off my gen and lost all 12V power in my 04 HR Imperial. We were able to jump the solenoid located in the passenger side rear panel (same compartment with the battery kill switches) to get me through the night.
In the morning we checked the salesmen switch and relay (located in the compartment under the drivers window) and everything seemed to be ok other than a blown 5 amp fuse on the solenoid which we replaced.

Here's where things get weird. We made a more permanent jumper wire with quick disconnect (in case something went wrong) to get me home.

Fired up the rig to build air. Went to shut off the motor & the key would turn to the off position but not shut off the motor. Disconnected the jumper wire and motor shut off. Reconnected the jumper wire & started the gen to bring in the slides. With the gen running I started the motor & this time with the gen running I was able to shut off the motor with the key. Fired the motor again with gen on.

Got on the road and within 20 minutes the "Alt Charge" light came on. Turned off the gen & light went off for rest of my 200 mile journey.

When I got home, again, the key would not shut off the motor. I hit the gen start button and the second I did the motor shut off. I then went to turn off both battery kill switches and the one on the right turned off however the left one would not turn. I then disconnected the jumper wire.

Any assistance or advice is appreciated as I've very confused! Also, if anyone has a wiring schematic for this vintage or advice as to where I can get one it would sure help.

[Robi.1014]

Excellent write up....which presents the opportunity to "break it down" into pieces as to what might be going on... So here goes.

Your paragraph 1:
When you shut-off the GenSet at the Q and lost all 12V service to the coach, that implies that the DC-path from your house batteries to your house circuits failed somewhere. My '04 Dip has a "120A House Breaker". I think that this breaker (or its wiring) failed on you. So when you put a jumper in place across the big solenoid back there, you began powering the coach with your starting batteries.

Next paragraph:
>"Fired up the rig to build air. Went to shut off the motor & the key would turn to the off position but not shut off the motor."
Unusual, yes. You know that before diesels were controlled by computer (ECU), you had to shut them off by starving them of fuel or air (or both). So somehow, with your jumper in place, you created a DC path to your ECU and it continued to run the diesel even with the key off. Can't explain it any further than that.
>"Reconnected the jumper wire & started the gen to bring in the slides."
The GenSet starter juice normally comes from the house batteries....but I think your house batts are "off line" due to an open circuit (the 120A breaker, etc.). So in this case, starting voltage for the GenSet came from the starting batteries through your jumper. FWIW, you don't need to run the GenSet to operate the slides anyway, right?
Next paragraph:
>"Got on the road and within 20 minutes the "Alt Charge" light came on. Turned off the gen & light went off for rest of my 200 mile journey."
In this case, the GenSet is running, producing AC current to/thru the Inverter. The Inverter is now doing its job...which is to charge the house batts. BUT, there is no connection to the house batts...but THERE IS a connection to the chassis batts thru your jumper. So you've got the Inverter and the alternator attempting to charge the chassis battery bank. I think the alt-light on your dash was an indication that the alternator regulator was asking WTF?...and turned on the light. When you shut-down the GenSet, the alternator went back to doing its job correctly.
Next paragraph:
>"When I got home, again, the key would not shut off the motor. I hit the gen start button and the second I did the motor shut off." The no-shut-off explained (kinda) above. WRT "I hit the gen start button", I think that the starter current (required by the GenSet starter) pulled-down the ECU input voltage just enough to allow the main engine to stop running. Again recall: the GenSet is/was being started by the chassis batts because of your jumper.
>"I then went to turn off both battery kill switches and the one on the right turned off however the left one would not turn."
Now was my "ah ha" moment. Up above I challenged that your loss of 12V to all house services was a failure of the 120A breaker and/or related wiring. Perhaps it was related to a failed House Cut-Off Switch (the one that won't turn). Whew.

So place a 12V meter across this c/o switch (while it's in the ON position) and there should be virtually no voltage across it. But it you read 12VDC, then this switch has failed. Perform this test without the Inverter being in service (e.g., disconnect from shore power and don't have the GenSet running).

[KenJim]

Ding, ding, ding...we have a winner! Thanks Robi for the very informative response to my post.

Tonight, I went back to the C/O switch and tried again to turn it with the same amount of force as yesterday. This time for some reason it actually turned to the off position. I then turned it back on and half way to the on position the light in the bay flickered. All the way on and no 12V. Needless to say I have 2 switches on order and will have it fixed by the weekend.

Thanks again Robi. It's nice to have a place to get sound advice.

["007"]

I could also be your solenoids that the C/O switch is operating.
Could have dirty contacts in solenoid if you can't clean them than have to change solenoid.