Sheeze. These old original equipment lights on this trailer Gale abandoned forever ago appear to have had the problem of a short in the license tag light. But the harnass was cut off up front I’d guess because it was blowing his fuses in the vehicle, and he’s been using add-on magnetic held lights.
So what I’ve got is four wires up at the tongue, a brown, white, green and yellow. The white’s ground as nearly as I can tell. The green and brown are both somehow significant because combinations of them with one another and each of them with the yellow will do things.
One combination lights all four tail-lights, one lights both bottom ones, one lights right-bottom, one lights left bottom.
Your average 21st Century man ought to be able to conclude something from all that besides the fact the lights get juice from the tongue to the rear and that all of the bulbs are good. Ought to be able to say, ahh. Now I know where to go from here.
But I’m damned if I’m that 21st Century man.
Old Jules
So Far From Heaven 