Electrical Issue In Coach

[technomayor]

I'm helping a elderly neighbor troubleshoot an electrical issue on his 2004 Ultra Supreme Class A. It has been sitting for a year or so. The interior coach lights (as well as all other 12v accessories) were not working. He suspected bad batteries (due to age) and replaced them and that did not solve the problem.

Here's one issue that has me stumped. When the coach battery disconnect switch is OFF the engine starts and runs/idles normally. When the coach battery disconnect switch is ON the engine starts and runs/idles but about every 15-30 seconds the engine tries to die. When it tries to die the voltage meter in the dash drops substantially.

Here's what I've done so far...
- Tested voltage on all batteries is approximately 12 1/2 volts.
- Checked every fuse and circuit breaker I could find.
- Started the generator and it output 120v as the microwave worked, but no 12v lights/accessories in the coach.

Any help you could provide would be greatly appreciated.

[GStream40]

First thing I would do is make sure all the wiring was connected properly at the batteries and that ALL the wiring was actually connected at all at the coach batteries.

There should be two battery systems, one is the house batteries (runs the 12 volt systems such as interior lights, water pump, etc) and the other is the chassis batteries.

Which batteries were actually replaced?

Ron

[technomayor]

The problem has been solved. A wire was swapped on the coach batteries.

Thanks for all your help.