65 dart turn signal wiring question.

That ought to be a clue. Something in the harness? Maybe "the pinch" melted some harness insulation and crossed some wires.
Looks like I may have to untape some wire on that harness and try to trace it down. Here's something else that is strange when I use my multimeter to check for continuity. I ground one lead of the meter and I touch the dark green wire with the other lead and I get continuity.