I have a 1969 chevelle. I am able to keep the lights on all of the time on the low beam setting. But when I switch to my high beams, after about thirty seconds they start to cut in and out like, until I switch back to my low beams again.

Any Suggestions?

Are you running some of the newer extra bright headlight bulbs? What is happening is that there is a circuit breaker in the head light switch. The extra current is tripping it until it cools then it resets. This causes an on-off-on effect.

Thanks for the info. I didn't know that. Unfortunately I don't have more bright headlights then stock, but my headlight switch has been giving me other trouble so that propably is what is going on with it. Thanks for your advice.

For what it's worth, an original Chevelle owners guide says the headlights (and parking lights) on original cars are protected by a thermal circuit breaker built into the headlight switch (as you suspected), excesive current flow will cause curcuit overflow (blinking) and warns of a probable short in wiring system (does not give clue where). For what it's worth. T.