Headlight Issue
 

I'm having an issue with my headlights flashing off and on when I turn the highbeams on via the floor switch in my 1981 shortbox. Headlights are normal without the use of highbeams, they dont start to flash off and on until the dimmer switch is used to turn the highbeams on. The two blue lights on the cluster also flash with the headlights. The dimmer switch is brand new and is not the problem. Tried switching negative battery cables and alternators and no change. Battery is also new. Any suggestions would be greatly appreciated.

Re: Headlight Issue
 

Hi Vern,

The headlight switches in these trucks (and many other GM vehicles) have a built-in auto-resetting circuit breaker.

If you're running aftermarket "high output" headlights that draw more current than stock, that could be overloading the switch and kicking out that internal circuit breaker. Since it's auto-resetting, that'll make the lights flash like you're seeing happen.

But if you're running stock type headlights, it could be that the circuit breaker in the headlight switch is just getting weak and kicking out under the increased current of the high beams vs. the lows.

Re: Headlight Issue
 

Thanks, I'll give it a shot.
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Re: Headlight Issue
 

Agree on the circuit breaker being the issue. New switches are dirt cheap.

It would also be a good time to do headlight relays to reduce the current flowing through the switch.

Re: Headlight Issue
 

Where abouts are the headlight relays? Swtich fixed it, I had a spare kicking around. Thanks ray_mcavoy

Re: Headlight Issue
 

Thanks for posting this. I'm having a similar issue with an 80 LUV. My headlights blink intermittently, somewhat more often while in high beam mode. I've replaced headlamps, high/low/turn-signal unit, turn flasher, hazard flasher, cleaned the battery ground at the frame, cleaned the fuse box terminals, and cleaned many other connectors.

Are your referring to the light switch, as in the on/off push/pull knob? I've swapped that too; however, it's used but was in better condition.

I'm not really sure if there's a circuit breaker for the headlight switch, or headlight relays. i'll return to the haynes manual.

this post has already given me something to research though. Thanks.

Extra thanks, because I realize the LUV is really and Isuzu. I have owned 68, 73, 80 chevy trucks and an 86 Suburban. Cheers.

Re: Headlight Issue
 

I replaced the headlight pull out switch, fixed my problem.
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Re: Headlight Issue
 

cool, thanks. tonight, i noticed the switch is getting hot when the lights blink, so i'll bet it's corroded or worn.

Re: Headlight Issue
 

If the switch heats up, it's toast. It happened to me once and I burnt myself pretty nicely. Replaced the switch and it fixed everything.

Re: Headlight Issue
 

I was having issues with my high beams as well, i wired them to a rocker switch i placed on the cluster and ran it to a relay then all new wire to the hi beams and no more issues.