Brake lights work, but not when headlights are on (Help) 1972 Dart

[Jacob]

Hello all! I just got my Dart back on the road this year, but I'm having a couple issues with the rear lights. At the moment, the car has brake lights if I'm just driving around. But if I turn on my headlights I do not get rear running lights. I was also informed today from a guy driving behind me that if I have my turn signal on and apply the brakes that my car toggles back and forth almost as if I have my hazzards on. I'm wondering if anyone has ever ran into similar issues? Suggested fixes? Should I just be looking to replace the rear wiring harness? If so, where did you all buy one from? Thanks again for all the help FABO, excited to cruise this beast through campus at night once I get this all sorted out.
-Jacob

 

[MoparMike1974]

I would start by checking any grounds for good connection.

 

[TrailBeast]

Hello all! I just got my Dart back on the road this year, but I'm having a couple issues with the rear lights. At the moment, the car has brake lights if I'm just driving around. But if I turn on my headlights I do not get rear running lights. I was also informed today from a guy driving behind me that if I have my turn signal on and apply the brakes that my car toggles back and forth almost as if I have my hazzards on. I'm wondering if anyone has ever ran into similar issues? Suggested fixes? Should I just be looking to replace the rear wiring harness? If so, where did you all buy one from? Thanks again for all the help FABO, excited to cruise this beast through campus at night once I get this all sorted out.
-Jacob

Whenever I have any problems like that I ground a wire somewhere in the trunk and start touching light bulb bases and housings wit the end.
It points out bad grounds real quick.

 

[67Dart273]

Ground the lamp sockets