74 Tailight Problems

oh this is a pain all right, how does the harness look? chopped up? some PO added a trailer harness? Is this something that just "happened" or are you putting the car back together and just noticed it?

Get the wiring diagrams for as close to your year as possible, and start comparing them with what you have.
Keep in mind that the rear harness may doesn't use black for ground, my 73 uses grey for ground..or is it brown...glad I could help :lol:
Could be as simple as the tail light switch..mine had so much corrosion on it, that it melted the switch and eventually blew the fuse