So I have a "new" truck, a '92 F-250 diesel. I was driving south towards Minneapolis last night when I noticed that my headlights keep turning off and on. Sometimes slow. Sometimes flickering. The DRL stay on, so I wasn't completely blind but I still had to pull over and sleep at the side of the road. No other lights do this.

Both lights go at the same time, so I'm guessing it's at the power box. I put a new fuse in. No luck. Beat the power distribution box with a 5lb hammer. Still not working.

I'll be in Minneapolis until Wednesday before picking up my trailer and heading home. I think I'll have a go at it again, in daylight.

 

Replace the headlight switch. I'd use a real Ford junker before a new Taiwanese switch, but that's up to you.

 

Funny, my 90 is doing the same thing.

I rarely drive at night with it, but they are supposed to be on in rain by law...
So lately I have been dealing with blinking.
Usually the person in front of me thinks I am trying to wave them down or something a will start throwing their arms up like "WTF".

I thought it might be the light switch, but what was throwing me is that no other lights but the two headlight bulbs are affected. ???
So I was going to look for a loose connection in the forward harness or something.

One thing I noticed on mine...
It only happens after the lights have been on for a couple minutes.
When they are first on, they are fine. Then they will start going on/off more and more the longer they are on. It eventually becomes a fairly rapid flicker and they spend more time off than on.

 

Mine's the same. Works for 30-60 minutes and gets worse from there. I can get it to work for a few minutes by turning it off and on. After a while it's a friggin strobe light. Everyone coming the other way slows down. They think there's a speed trap ahead.

I don't have a new switch and I won't likely find one in downtown Minneapolis. I'll pull it out and see if I can find anything ovbious wrong with it.

Thanks Steve. This forum rocks.

 

Don't waste the effort - the circuit breaker is internal, so you won't see anything. Just replace it.

 

Done. I'm in downtown Minneapolis, so I had to go with the Made in Taiwan version.

Fixed. Thanks. On to the @#$@# trailer brakes.