hello,

i have a very strange problem that i have no idea how to even go about fixing..

I have a 1990 F250 xlt 4x4 that recently decided to annoy the hell out of my by randomly shutting off and turning on the headlights. It seems that when i have been driving for a while on the highway or back roads, independent on bumps or anything banging around, the headlights of my truck blink on and off at different intervals and at different durations.

Also, i noticed that as it's going crazy if i use the **** and shut the lights off manually and then turn them back on again, they stay on for a little while and work correctly. But after a while of driving it happens again. i have checked all the connections to the lights and they seem fine. I have overhead lights on the roof that do not go out when this annomaly happens.

It's almost as if the lights get too hot and are being shut off by a head sensor of some kind then come back on and get too hot again and shut off again etc... and when i hit the switch to the lights they cool down enough that when i turn them back on, they work for a while..

i do not understand what could be going on and have tried my best to describe the problem. If anyone could please please please give me an idea of what is going on i would greatly appreciate the help

thanks
-Todd Staples
1990 F250 xlt
Massachusetts

 

The headlights have a circuit breaker in the fuse box. It is designed to do that type of on/off instead of opening the headlt. ckt completely while driving. You may have a short somewhere. Also, a ground for the headlt. ckt may be loose or corroded. And the last check could be the headlight relay itself. A ,loose connector could be the prob here.
Good luck,
Al

 

Based on the my experience I would remove the headlight switch and look for melted terminals on the harness where it plugs into the switch. Repair with NEW plastic piece and new wire terminals where needed. Soldered connections on wire repairs only. If no problem found you could try replacing the switch. Problem could be inside where you can't see it. My 2 cents.

 

i have a 1994 f 150 that does the same thing I noticed that after @ 30 minutes or so they will blink but come back on before i can do any thing but I noticed the orange glow of the park lights were still on last time i just recently replaced the pull switch but havent driven long enough at night to tell if it worked it was $11.00 or so also i was told to try the dimmer because it first happened on brights but that is $58.00 good luck dcoker18(No Email Addresses In Posts!)

 

there is a circut breaker in the switch, a new switch is usually the fix for this, doubble check the conector when replacing the switch.