[Wavery]

There is a switch on the top of the bottom bathroom wall. When you put the upper (back) part of the wall in place, that activates that switch so that the lights (in the back roof shell) will operate.

It is a simple job to remove that switch and check it out. If it's faulty, it is easily replaced.

If there is no current to that switch, it's a short run (maybe 20") to the converter and fuse panel. I am assuming that he checked the fuse.

If the switch is getting current, functioning properly but no current is getting to the lights, it should be easy to ID the offending wire with a multi-meter. It is fairly easy to pull a new wire if need be. However, I doubt that is the problem.

I would check the wire bundles on the outside of the camper, in the back, where the roof support hinges are. They come out of the lower shell there and enter the upper shell. That would be the most likely place for a short or broken wire as the wires are exposed and they chafe each time the roof is raised and lowered.