headlights intermitent

[rangerdanger]

1967 f100
My headlights go off when im driving then come back on 5 secs later. If i turn the lights off and then on again they work. Then 30 to 60 secs later the same again. Battery is new no other electrical problems. Has anyone experienced this before? It is very scary driving at night on country roads i can tell you!
Pete

[ForingaMex]

You are not alone rangerdanger,
The problem you discribe is very common in our trucks and your right, it is scary on dark nights. Most likely (95% sure) it's your headlight switch. The headlight circuit doesn't have a fuse in it but the switch has a breaker inside and when the switch get old the breaker starts to act up like that. A new switch should fix your problem. Hope it helps.

[mrsnicks]

I agree with ForingaMex... although in some rare cases it's the high beam switch that causes the problem.

Patrick

[ForingaMex]

agree

[mr_josh]

Those guys are right and here's a funny story: right after I got my truck on the road, I went and picked up a dog that my family was going to "test drive" overnight to see if she would be a good fit. It was the proverbial "dark and stormy night" and we're rumbling along out in the country on our way home. Go through a bit of a curve and approaching an intersection, and then: lights out. I knew right away what it was but had never had it happen while driving... pretty scary. I swear to you, I heard that dog say, "Oh sh!t..."

[fordman]

replace the headlight switch and or the dimmer switch or get a headlight relay upgrade for the truck.

[RidgeRunner13]

I am currently going through the same problems, but when I replaced the switch my tail lights quit working. The switch CQ gave looks the same as the original except it does not have a "U" shaped bracket on the front of it. I found a way to eat the distance up so the switch would set snug.

Any ideas what is wrong, or just the wrong part?

'72F100C w/ '72F250XLT body

[fordman]

it could be many things. it could be a bad switch even though it is new. it could be the wirng in the plug isnt making good contact. it could be that soemthign else got jarred when replacing the switch. the u shape bracket can be knocked off of the old switch and put on the new one if you are carefull when you reinstall it.

[Dragon]

It does not have to be old to have that problem. The headlights when using 6024 Halogen bulbs is 11 amps and when you add taillights and front parking lights added in you exceed the 18A and even a new switch will cycle if you get close to 18A. The later switches don't have the circuit breaker.

A standard incandescent 6014 bulb draws 3.7 amps in high beam.