My turn signals on my 70 work flawlessly except that when the headlights are on, the opposite indicator on the dash will blink even though the correct turn signal lights are flashing on the car.
With the headlights off, the correct indicator blinks and the correct signals blink.(no problems) Any suggestions? All my other gauges and lights work fine. :confused:

Any wild guesses? Could wires have melted together somewhere?

I would check the dash grounds. Perhaps John Muha or Elree will have other ideas.