I do not know how, but I lost all 12V in coach. I have 12v when the gen is running but if I turn off gen the 12V is off. I can not locate master switch - if any.
Locate the relay that you hear click with aid of a helper. Check voltage on each side testing on large posts. When closed, the voltages should be the same. When open they should show different voltages. If the voltages are not the same the relay is bad. Make sure test it in both positions.
The battery switch, by the door, is going to solenoid. The solenoid work. I check the voltage with on and off. Somewhere I lost connection to control box. Are you suspecting that my charger may have something to do with?.