View Full Version : headlight issues - im stumped

08-10-2009, 11:46 AM
This is on my 99 suburban.

Daytime running lights work...but when headlights are turned on, DRL go off neither low or high beams work, only running lights. Ive tested the switch itself by swapping out the one from my 95 truck that i know works. What else could be wrong. Im not sure what else to look for.

God prefers Diesels
08-11-2009, 11:45 AM
Since every thing works, and we know they didn't both burn out at once(you haven't crashed into any large structures at high speed right?;) ) I would say...

1. Something is unplugged or broken that is exclusive to the headlights.

2. Bad fuse. I fixed a Dodge with one headlight that would work, but it was vewy vewy dim. Turns out the fuse wasn't even in the hole. How'd it work at all? It's a mystery to even God!!!!! But I put a fuse in the hole and can I say: "Let there be light??" I was happier than a tornado in a trailer park.:D

08-11-2009, 05:34 PM
Check the relay under the hood

08-12-2009, 03:23 PM
Where is it located? Ive looked in the fuse box under the hood, but didnt see any relays for the headlights...

08-12-2009, 09:04 PM
...a "headlight" relay it's a "drl" relay...if the drl system is working properly you don't have to "turn on" the headlights...they should already be on...

Garth J
08-13-2009, 12:09 PM
There is a switch on the parking brake that switches from DRL to headlights ON check that one too...G

08-13-2009, 08:50 PM
The DRLs are working...but if i turn on the headlights, like to use the high beams of something...then there are no lights at all. The Low beam lights that are on with the DRL turn off when in fact they should stay on.

Garth J
08-13-2009, 11:25 PM
so many things did you check the dimmer switch?

08-14-2009, 09:07 AM
Yes, Like i said i replaced the light control with a known working switch from my truck...It works fine in my truck...but no lights in the suburban. I also looked for a DRL relay....but no shuch thing exists. Only found a DRL fuse in the panel in the cab.

08-15-2009, 07:05 AM
Hi John !

IIRC the DRL are the HIGH beams - only dimmed ! Not the low beams !

Perhaps, there's the source of the problem hidden ?


08-15-2009, 10:23 AM
...wifes' 01 burb drls' come on with key on...headlites-parks everything that runs with headlite switch.."dimmer"switch works hi to lo beam and lo to hi beam...on early models equiped w/drls 1 notch down on e-brake would disengage the drls...I don't think that applies to 98up....having said all this the problem could be in the multi-function switch...dimmer-turn-w.s.w/w...we've had this burb for a year and neither one of us has ever "turned on" the headlight switch...

08-18-2009, 06:25 AM
Yes one click on the e-brake disengages the DRLs. Is there some sort of switch in the steering column connected the the turn signal/high/low beam lever that could be causing problems?

10-11-2010, 10:21 AM
ended up replacing the turn signal switch. headlights working now.