Good day y'all.

!966 f100

From the factory harness connector at fire wall, closest to drivers door, inside engine bay, there is a green w/red tracer wire and a green w/black tracer wire.
The green w/red goes to the voltage regulator.
The green w/black goes to headlights.

When those two meet inside the harness connector inside the cab, the green w/black tracer wire goes to headlight switch, the other wire is a PURPLE resistance wire.

Not the pink one which goes to ignition.

Where in the heck does this purple resistance wire go?

I am not finding anything in the three schematics I have.

Any insight would be great.

Thanks,
Aaron