Turn Signals Fail to Work

Hi,
I have a 1970 Cuda, the turn signals work fine when my headlights are off. But, when I turn the headlights on, they fail to work. Any idea's would be appreciated.
Thanks, Dave

ground.

I bet fails also on PARKING LIGHTS position and not just headlights

What is the best way to track down a bad ground? With the parking lights on, they blink but slower.

ok, on my Charger the main ground point is at radiator core support BUT parking lights is as mostly of cars CHASSIS grounded, being the wired ground really just for headlights.

Can't remember if Cuda parking light housings are plastic or metal AND if the housing gets some good body place to the ground. Will need to check every parking light housing for a propper ground.

Some other laters got a wired ground to reinforce the chassis ground.

Check anyway the radiator core support ground too being the negative battery wire gets that point too and thats a chassis ground reinforcement.

Dunno if rears are also chassis grounded too on a 70 Chally. I know 71/72s Charger tail lights are metal, taking the groung by the chassis, diff than 73/74 Chargers with plastic housings. If plastic, then somewhere on trunk must have a ground place to tail lights and sidemarkers.

Your Battery ground cable should have a small wire off of it grounded to the radiator support right by Battery.