Headlights?

[Doubletop]

87 GMC with the quad headlights. Driver's side top light goes out when brights activated. It works fine on low beam. I've replaced the light and verified it's the right bulb cause it's the same as on the passenger side. Any ideas?

 

[Rickf]

I thought some trucks w/4 headlights only allow high or low beam not both. I could be wrong, I'm old.

 

[Craig 85]

I thought some trucks w/4 headlights only allow high or low beam not both. I could be wrong, I'm old.

That's only on the 89-91's. @Doubletop are you getting power at the connector?

 

[Doubletop]

That's only on the 89-91's. @Doubletop are you getting power at the connector?

The light is on with low power and only goes out when brights are turned on. So if I'm getting power with low beams wouldn't I still be getting power with high beams? Sorry, electrical work is far from my specialty.

 

[PrairieDrifter]

No the high beam circuit is a different circuit so there's an issue in that wiring. Low beams will be on low beam mode and high beam mode. while high beam lamps only come on while in high beam mode.

 

[Craig 85]

There is a high beam switch on the left side of the column. I know we have the thread on it, but I found this one first on the internet. It will give you some info on where to look. It could also be the headlight switch. There are a variety of videos that explain how it works.

http://forum.73-87chevytrucks.com/smforum/index.php?topic=30639.0

 

[Doubletop]

Thanks guys. Leaving town for the next week but I’ll try these suggestions when I get back.

 

[Joe Smo]

Check your switch but I bet its a bad ground wire.