70's Wilderness Travel Trailer light wiring question NEED HELP QUICK!

[Airborne29th]

Sorry for the confusion. I am going to tackle it today with a test light. When you say test the back of the light, do I just ground out the clamp of the test light and then touch it to either the red or the green wire on the back of the light? And that is what I mean by red and green is all I have on the back of the right light. 2 wires, no ground. The left light has 4 wires, red, green, thin black, and thick black. I believe the thick black was grounded out on a screw to the metal siding of the camper when it was installed to the wall, the thin black I'm not sure where it went.

[ahicks]

The thin black, wild guess, might be for back up lights?

Regarding the ground wire on the side with only 2 wires - you should be able to use the metal skin for a ground - but I would look for/check out where the main ground (coming from the tow vehicle) is fastened up front. That's often done on the first metal cross member, you want to make sure that's a good connection. Not a wad of rust.

Regarding the test light - use it to figure out what the wires on the back of the trailer are doing? Once that's known, that should allow you to hook them to the light assemblies correctly.