I have a 1991 F-150 and couple days ago my low beams quit working. I have high beam, but no low beam?. How do I check to see if it is a bad dimmer switch vs. bad headlights? The lights look like bulb instead as the old headlight piece.

 

both lights at once? very coincidental, so i doubt it's the bulbs. still, i'd pull 'em just to check. wierder things HAVE happened. also, check your fuses.

Mike

 

Yes Whitey that's true. So should I use a test light on the dimmer switch? Thanks.

 

probably be a good place to start. what about the hi/low beam switch? do you get the little blue headlight icon coming on and off when you click it?

Mike

 

Yes...when on high the little blue light is on....when off it's out

 

TTT for ya. I just picked up an '89 yesterday and have the exact same problem, no low beams (bulbs look fine) high beams work and hi-beam indicator comes on. Is this a somewhat common problem?

 

...Welcome pickupfish, to Ford Truck Enthusiasts!

Enjoy FTE....see you on the boards.

 

Check the connections at the bulbs, and check the ground. If those are ok, then check the dimmer switch on the floor.

 

Thanks Tim, I'm happy to be here! Love my first ford truck so far...
pfogle: i'm now 90% sure its the dimmer switch