Mystery wire in headlight harness

So best I can tell, that green with tracer wire is a leftover from 1968 when there were marker lamps in the fenders (I think someone up above said as much). If you look at a Charger or a Dart diagram from 1968, you can see it. So it appears it is NOT a "key on" wire. I will check it tonight with the light switch. Theoretically, when I turn on the lights, this thing should have continuity with the battery wire at position J


Yes,

Dark green/ white Trace from Z terminal is for 68 marker lights and park lights. See drawings attached.

Page 4.

You either have a leftover early production harness or more likely it has been swapped over the years. I would guess the later or incorrectly ordered replacement.