I don't know if you could consider this a "fix" but the PO of my truck used about six different lengths of wire to get power from the dash to the tail lights. Among these was a section of lamp cord with two isolated wires in the same rubber casing. He just split it at the rear axle and branched it off to either tail light. He also seemed to have something against electrical tape. There were three or four places where the bare copper was just twisted together to splice two wires together and just left like that. I nearly had a fire beneath the dash and that's when I ripped every last piece of the old wiring out.

1956 Chevy 3200