Once worked on a '78 (?) Caddy Seville, had no back lights. Found that the car had been clipped in it's lifetime, so the harness was suspect. I found the harness (GM used aluminum hard wires in those harnesses) cut in the middle, both ends stripped and inserted into rubber vacuum hiose so they butted, and taped so the wires wouldn't move. I think that's the worst wiring repair I've ever seen. Butt connectors would have been an inprovement.