Hey Darling: Check your grounds. For the sake of trouble-shooting what I'll often do is grab my jumper cables and start by clamping the neg jumper cable to the neg battery post and bring the other end to the point where I'm trouble-shooting, using that as my connection point for a temporary ground, until I can isolate the rest of the circuit. It's amazing how age and rust between all those frame and cross member joints and body joints affects continuity eventually. Just like with a boat trailer that's been in and out of the lake a thousand times. Sometimes its easier to just run a dedicated ground back there to the tail-lights and then the other end back to the negative post. Good luck.
_________________________
