I'm out of ideas... the low beams on my 1990 F250 (460; 7.5L) are out, but the parking lights, tail lights, and high beams work.

I've tried a new light switch, fuses, new bulbs, checking for grounds (that I could find), but nothing helps.

When I pull the light switch out, to turn the low beams on, a relay "pops" in the engine. It's called the trailer tow... I tried a new relay for it, but it still pops. I can't figure out what to try next. Any thoughts?

 

If I recall correctly, the headlight dimmer switch is located on the floor activated by the left foot. You didn't mention if you had checked there, but if not that would be a good place to start Many times moisture and sediment accumulate there and will cause problems. When you say pops, what is it doing? If it is not causing a fuse to blow then you may need to either start checking from the dimmer switch out to the headlights or work back from the headlight low beam wire to see just where the wire is fed with power. If it is from the relay you can confirm wire integrity from there to the headlights . Let us know what you find and if not the problem we can go from there.

 

I have NOT checked the high beam switch (located on the driver's side floor). I never thought to check there. When I say "pops", it's a clicking sound coming from the plug/relay titled "Trailer Tow" on the plastic housing that holds some relays. It clicks whenever I pull the light switch to turn on the truck lights. I will check the high beam switch to see if the problem is there though. Thank you.

 

hanky... THANK YOU!! I finally got around to checking the dimmer switch on the floor. Went to advanced auto and purchased a new one, popped it on, and LOW BEAMS WORK! I can't believe it was that easy... I searched everything else, but never thought of that (because it worked). Problem solved! Thanks again! I learned a lot in my search, and fixed other electrical issues so, it wasn't all for naught. God bless!

Rich

 

Thanks for the update, you probably knew all this , but just didn't think of it at the time.

 

I didn't know this at all, hanky. I'm not a mechanic... just don't have the money to spend on a shop so, I'm self-taught (YouTube, forums, etc). Necessity breeds action!! I appreciate your help immensely. Thanks again and God bless!