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Daytime Running Lights not working

jeb
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jeb Enthusiast

jeb

Posted
Posted (edited)

I did some searching, but could not find what I need. I have an 04 GMC Yukon XL SLT (3/4 ton, 4x4, quadrasteer) and the DRL's just do not work anymore. I see lots of folks wanting to disable them, but I'd like to get mine working again.

 

I pulled the socket on one side. The socket was a little blackened around the bulb, but still in good shape. Both bulb elements tested good with my Fluke meter (although it appears the socket can really only power one of the elements, so not sure why there's a 2 element bulb in there). I get no power to the socket terminals. Engine running, in drive, sunny day with the lights on or off. Nada. They do flash when I lock/unlock the truck, though. I changed the fuse and the relay for the DRL's, but it made no difference.

 

If they didn't flash with the lock/unlock, I'd suspect a wire. But it's got me kind of mystified at this point.

 

Any hints on what to look for would be appreciated. Is there an online wiring diagram for these trucks?

Edited by jeb
txab Senior Enthusiast

txab

Posted
Posted

The DRLs have worked before while you've owned the vehicle? If you're not the original 4114 is the bulb #

 

Make sure your emergency brake isn't applied even just a notch or two. More later...

jeb Enthusiast

jeb

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Thanks for the reply. I did make sure the parking brake was not on.

 

I've owned the truck since new, 86k on the clock. Always babyed it. And yes, the DRL's for sure used to work. I'm not sure how long they've been out.

tesnoboy Enthusiast

tesnoboy

Posted
Posted

Usually the parking lights flash on lock/unlock not the DRL, unless they changed it on your year-2004. I put the 4157NALL in mine. Looks better with amber. Don't know why they use the 2 filament bulbs, maybe need the heavy filament for the brighter light. Do your auto headlights still work? I was thinking maybe the light sensor on the dash might be screwing up. I had to bypass mine, it was keeping the headlights on all the time.

sonjaab Senior Enthusiast

sonjaab

Posted
Posted

Also note that certain year DRLs only turn on when truck is in gear.

Can't remember when my 04s came on................

txab Senior Enthusiast

txab

Posted
Posted

Tesnoboy picked up on something. You said they flash when lock/unlocking. As he stated only the turn signals flash. The DRL will illuminate when it's dark, but they won't flash. Are you checking the correct bulbs? Lamps are closet to the radiator grille opening.

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

DRLs only work in gear. Put the truck in drive and I think you can set the parking brake and still have them work. I did this with the key on/engine off to check mine on my 2003. I think. Traded it in 2008 so it's been a while. :lol:

txab Senior Enthusiast

txab

Posted
Posted

DRLs only work in gear. Put the truck in drive and I think you can set the parking brake and still have them work. I did this with the key on/engine off to check mine on my 2003. I think. Traded it in 2008 so it's been a while. :lol:

 

 

Engine running, in drive, sunny day with the lights on or off. Nada.

 

 

He's already done that Mike. :)

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

Oops! Well they shouldn't flash when you lock/unlock I'm pretty sure. But I'm gonna bow out since I can't seem to read tonight. :lol:

 

 

Sent from my iPhone using Tapatalk

jeb Enthusiast

jeb

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Sorry for the late reply, and thanks for the input. Dirt bike races have been consuming me of late, so not getting online as much.

 

Yes, the auto headlight sensor does work as normal. Tested several times now as I'd read that was a possible cause.

 

The signal lights also blink when I unlock/lock the truck. The DRL lamps come on with them, and stay lit for 10 or so seconds after the signal lights go out. Backup lights stay on solid like the DRL's for the same time duration.

txab Senior Enthusiast

txab

Posted
Posted (edited)

Sorry for the late reply, and thanks for the input. Dirt bike races have been consuming me of late, so not getting online as much.

 

Yes, the auto headlight sensor does work as normal. Tested several times now as I'd read that was a possible cause.

 

The signal lights also blink when I unlock/lock the truck. The DRL lamps come on with them, and stay lit for 10 or so seconds after the signal lights go out. Backup lights stay on solid like the DRL's for the same time duration.

 

 

This happens during daylight? The DRLs remain lit as you descrobe? Are your headlights on all the time during daylight? Sounds like the ambient light sensor is bad, tricking your system to think it's dark

Edited by txab
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jeb Enthusiast

jeb

Posted
  • Author
Posted

The DRL's and backup lights staying lit for 10 seconds after unlocking the truck happens in dark or light. I'm pretty sure they have always worked that way. The headlights are for sure not lit during daylight. I have no lights on at all right now in daylight. The headlights do come on automatically when it gets dusk/dark. The ambient light sensor seems to be funtioning as it should.

txab Senior Enthusiast

txab

Posted
Posted

During daylight conditions the DRLs shouldn't illuminate at all when unlocking or locking in my experience. When my ambient light sensor failed, my DRLs illuminated during the day as you describe, but also my headlamps were on all the time as well

jeb Enthusiast

jeb

Posted
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I just tested it. You are right that the DRL's do not come on when locking/unlocking in direct sunlight, but do in dark conditions.

 

So there seems to be no question that the ambient light sensor is good.

 

Fuse is good. Relay is good. Bulb and wiring are obviously good or they would not come on at all.

 

Anyone know of wiring diagrams online for these trucks?

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