73 challenger turn signals

[lcb73]

When the headlights are on, the turn signals will not work. Forgot to mention that they work with the headlights off.

[73chalngr]

Is your battery fully charged ?  Or rpm's low ? That seams to be the only time I have a problem like that. A member on here sells relay kits for the headlights they might help with that problem. I have considered buying for my car .

[anlauto]

I have the exact same problem, at least it sounds like it...
https://forum.e-bodies.org/electrical-and-audio/11/weird-electrical-issue/25620/

[jimynick]

Put a meter on them and see what you get in both those situations. I'd also run an auxiliary ground too, and eliminate some variables.   

[dodj]

Is this engine running, or off?