That's a good point about the tow wiring. Someone DID splice in to the lights for a tow connection, then cut it off and covered it in electrical tape. I need to inspect it closer.

I did find the chassis ground on the passenger rear turn signal was non-existant. So I cut all the ground wires on both signals, spliced them together, and reconnected them to a clean ground on the chassis. I hope that didn't screw anything up! lol