Solved: Issue with lighting

[1970A-66Challenger]

Just putting electrical power to the challenger after a long restoration.  I've got the wiring diagram and started troubleshooting but I figured one of y'all could maybe save me some time and aggravation.

When I turn the headlights on, the passenger side turn signal indicator in the dash stays lit and the passenger side turn signal light goes dim. I figured it was the turn signal switch which I previously replaced but the problem persists even when I remove the switch as shown in the picture.

When I move the turn signal cam to the passenger side, the turn signal indicator goes out.

Any thoughts?

[Rich G.]

Bad grounds.

[Chryco Psycho]

I agree bad grounds at the light housings to the body or the socket to the housing , often a small pin punch to seat the socket can fix the ground .

[RUNCHARGER]

Memory is foggy but it seems to me it is possible to mix up the side marker and signal/park light plug ins. Check them with a test light to be sure you haven't plugged them into the wrong ones. If not check grounds. The plugs are the same however the sidemarker has a hot and a ground, the signal light has a circuit for the park and a circuit for the signals, it grounds through the housing instead of a wire. Hence you can mix them up and it will do what you describe.

[1970A-66Challenger]

Rich G. and Chryco you were correct - poor ground on the right turn signal light housing.

What baffles me is there was a sufficient ground for the turn signal light to work perfectly but when the parking lights were turned on the turn signal light stopped working completely and backfed the instrument cluster light as those circuits are connected at the firewall terminal.  Definitely defied my "understanding" of DC voltage.

Thanks for saving me from tearing into the dash wiring!!!

[Rich G.]

Glad we could help and it was an easy fix. The ground circuit is a simple but common problem.

[Chryco Psycho]

The ground was never good , the turn signal was grounding back through the light circuit until the lights are turned on then there is no ground available

[1970A-66Challenger]

The ground was never good , the turn signal was grounding back through the light circuit until the lights are turned on then there is no ground available

Now it makes sense.