I bought a 66 convertible a couple of months ago. After the deal is made, seller casually remarks that I probably noticed the right blinker doesn't cancel (I did, easily fixable) and headlights work "intermittently" Anyone familiar with this headlight problem? After headlights are on for 5 or 10 minutes, they'll start to flash (on for a second or two, off for a second or two). It's both lights doing it together. Tail lights and dash lights, radio, etc., are unaffected and work okay as this is happening. Symptoms continue with the engine off and also when the car is parked. I know that there is a circuit breaker built into the headlight switch and it is self-resetting. Is this safeguard overreacting? Wiring harness under hood looks okay (but can't be sure); I haven't pulled the headlights or buckets off to check connectors or wires inside yet. So is it most likely to be a short/bad wire? bad breaker? voltage surge tripping the circuit breaker? Any help appreciated. (Car is 200 cid six, 3 spd, alternator)

 

It's probably that circuit breaker and what it's doing is overheating (turning off) then when it's cooled it's resetting. Replace it and check your grounds. You should be fine. As they get older the bimetal tab that's used as the trip switch in those breakers gets worn out or just plain doesn't work anymore.

 

Thanks for excellent explanation. I have switch coming, and replacement of that seems to be the first and cheapest solution to try.

 

I've got a '67, mine was doing the exact same thing.

Replaced the dimmer switch and all was good. Grounds were all good as well, the fault was in the actual switch, oddly enough.