Have chased down this problem for weeks with no luck. All overhead lights (12 volts) on doorside of 2004 Revolution do not work. Can take jumper cables from ground terminal under bed to ground terminal on light above bathroom sink and everything works so it seems to be a ground wire issue. Have put meter on hot side and get correct voltage. Thought I had this fixed when I ran new ground wire from adjacent fan ground to light fixture ground. All lights and fan worked. I left this for a few days and returned to find it no longer worked. Not opnly did it not work, my luggage compartment switch no longer worked with the appearance of internal arking. Hot side okay but ground side fried.
Local RV dealer not much help. Fleetwood sent me wiring diagrams. They help but they do not tell the entire story.
I consider myself reasonably intelligent (I'm an engineer) but I think this has just about beaten me!