My 97 F-150 Lariat's headlights go out and to turn them back on I switch on the high beams then toggle back to low beams and they work for a minute or two before going out again. I've replaced the dash switch with another and it didn't correct it. Any suggestion?

 

I THINK the headlight circuits are protected by self-resetting circuit breakers. I'm guessing switching to high beam allows your low beam CB to reset, but there is an abnormally high current draw in that circuit that causes the failure again. It's also possible the CB is just worn out. Unless you feel competent to troubleshoot electrical circuits, you should take your truck to someone who knows what he's doing.

-Jack

 

The Low beams are separately supplied through right and left fuses. Look at your user manual in the fuse section.
There are no circuit breakers in the light circuits shown on Ford Doc.
This is an attempt to not lose all head lite functions at the same time.
My suspect is a poor ground affecting both sides as a common point failure. The ground point heats up and goes open from the current it tries to pass.
Re-seat both fuses to eliminate that possibility.
As a note, the high beams are connected together to one power source. Their ground may or may not be the same point for obvious reason.

 

Thank you, Bluegrass, for correcting me. I had no quick access to the manual for that model year and was making a guess. Yes, if the lights are not protected by circuit breakers, then there would HAVE to be separate fuses to each. A poor ground is indeed a strong possibility. I hope the OP comes back to us with the actual cause.

- Jack