Electrical Issues

I think you have a loose nuetral (ground) wire. The way they throw things together it's surprising anything works. I had my ceiling lights go dim one night and I found it was a bunch of wires come together and fastened with an undersized wirenut. They where loose and some had fallen out. New larger size wirenut fixed it. Then I went through the whole camper and found simalar loose wires. Remember, a lot of motion goes on hauling down the road and things become loose. To test, take a single wire from the neg terminal of the battery and run to the lights. You really need a voltage tester and learn how to use one. Asking helps but testing is the only way to fix anything