Headlights go out after driving with them on for a bit

[Zukinut]

1968 f350. Non halogen lights, factory headlight switch and dimmer switch.

I've been driving the truck at night some now. After driving with them on for awhile they will randomly go off or flicker between off and on. Is this by chance a common problem.? If so what is usually the culprit?

I've had some issues with no turn signals and no brake lights that was fixed by cleaning the fuse block. There is no fuse for headlights so I can't do that.

Thanks in advance
Will

[johnboy72]

I remember my old 72 doing that when I was a teen. One time they went out and I just floored it to get home. Right past a Mo State Trooper who pulled me over. I was quick with the "My lights are acting crazy and I'm trying to hurry home to fix them or park it." Luckily for me I got off with a warning and he suggested I take a look at the actual light switch inside. Good guy and he turned out to be right. I replaced the whole switch off a parts truck and never had the problem again. I'd suggest a new one though.

[BobbyFord]

Time for a new headlight switch.

[Zukinut]

So, headlight switch and not dimmer? I'll get one ordered.

Will

[chad67]

I am pretty sure this is a common problem, my dad's '79 and '75 both had this problem. It was the switch. If I remember correctly the switch has a circuit breaker or thermal disconnect of some sort that eventually goes bad.

[Zukinut]

Sounds good. I'll replace it and see what happens.

Thanks again
Will

[CommrclDiver]

I had this same problem. Turns out all the shotty wiring that has been done over the years had overloaded my headlight switch. I replaced the switch and was still having the same problem. Bought a "heavy duty" headlight harness from LMCTruck.com. It uses the headlight high/low wires to operate some relays and has your headlights wired with a full 12v from the battery. No more overloading the switch and the problem gone!