I was warming up my truck at 4am in West Texas, about 40. I ran it 20 minutes or so, as I was shutting down my Camper. I turned on the headlights when ready to leave, nothing, except parking/running lights. I shut down and restarted, turned on lights, still nothing. I started to get the owners manual out to check fuses, and mysteriously, the lights came on and worked flawlessly for the trip, Thank Goodness!
I read a few related threads, possible light switch, possible bad ground. Any body else have this happen recently? I also run the brigheter light bulbs, same watts, forgot their name.
It almost seemed like a confused realy.

 

I don't have any lights when my relay gets confused & doesn't know which way the switch turned.

You can't see electricity or why ii is or isn't flowing so you need a meter. The combo switch is a good place to start.

 

This era is known for flakey high/low switch. Can be a bit disconcerting when you click off the highs and the lows go away too at 70 mph...LOL. Operate your high/low switch a few times if it happens again. Mine have always come back in short order.

 

do you have an upgraded headlight harness by chance?? i had a similar issue with a relayed headlight harness. well, not quite true - it was the connection which was bad (power to harness from batt terminal)

i suggest tracking down and checking ground connections . . .

 

I have an OEM wire harness. How does one go aboiut checking the ground connection?

 

My bet is also the multifunction switch (hi-lo). Quite common problem.
The open design of the switch allows gunk to build up on the contacts till they eventual short open.
I've had good luck fixing them by spraying electronic cleaner down in the switch while working it back and forth.
Unless you like fire disconnect batteries first.

 

Supr, I had the same thing happen to me in my 95, I had the silverstar headlights and just like you said ,warmed up truck turned on lights and nothing but the running lamps. Then they came on . I found out it was the light switch. I replaced it with a new one from autozone for around twenty bucks and never had another problem.

 

Ah yes the Electrical Gremlins have found your truck too...
Watch out they are sneaky little critters...
I had to replace my turnsig/Hi/Lo switch assembly to cure mine
but the main head light switch would be my first check

 

I second this with my 95. But I didn't know it was the switch until the headlights stopped coming on eventually. A new head light switch fixed it, and then the relay set up cured it forever (hopefully - been a year with no problems).

 

I fixed an intermittent multi switch w/ contact cleaner.

Floyd