DRL's and rear heat question

JJackson · December 4, 2006

Hi there, long time listener, first time caller.

I have a 1999 Tahoe LT 4 door Canadian model (if that matters) with Vortec 5.7, and have 2 questions.

1. The DRL's do not come on. There is the annoying green headlight symbol lit up on the dash all the time to tell me to turn on my headlights, regardless of daylight or lack of it. Obviously goes out when I turn on the headlights. I know about having it in drive and parking brake off, and I've checked the fuse panel. No dedicated DRL fuse. But they never come on, ever. I'd like the DRL's on, and the green light off. Any ideas?

2. Vehicle has overhead console with a fan selector only, labeled "rear AC". No temperature selector on the overhead. I get no heat back there, and am wondering is it not capable of pumping heat into the rear too? I only get cold air blasting back there, and just would have thought there should be a seperate rear heat system if there's AC back there. Sort of figured when I had the temp set hot up front I'd get hot back there too, but I only get cold air.

Anyways, thanks in advance. Hopefully the questions aren't too thickheaded.

JJackson · December 4, 2006

If memory serves me right, that green dash light is the indicator that the DRL's are on, not a turn your headlights on reminder.

<{POST_SNAPBACK}>

Yup, that's what it says in the manual too. But they're not coming on. Do the DRL's use a seperate bulb that could be both burnt out? I just thought of that.

I had a third question I forgot. The rear windows only roll down about 6" or so. Obviously some child safety thing, but I gotta believe they are capable of rolling down all the way. There's a switch on the door to disable the latch from operating from inside, but that's all I got.

Any other input is more than welcome.

GM-Tech · December 4, 2006

Yup, that's what it says in the manual too. But they're not coming on. Do the DRL's use a seperate bulb that could be both burnt out? I just thought of that.

The '99 Tahoe is the old body style, and those use the headlights for the DRLs. Yes, there IS a dedicated fuse. It's labeled DRL/Fog and it's in the fuse box on the left side of the dash. If it's not the fuse, it could be the DRL module, diode, relay, etc.

I can't believe the number of posts there have been about inop headlights or DRLs in the last few weeks. Seems to be a run on this problem. Do a search in this forum for other possible tips and answers to questions you may have. I'm done typing this stuff over and over again.

The rear windows only roll down about 6" or so. Obviously some child safety thing, but I gotta believe they are capable of rolling down all the way.

Had this complaint a few times. Step back a few feet and look at the glass and look at the door and mentally note the size of the glass and the size of portion of the door that's big enough to receive the glass... mostly the height. See anything that might be a clue?

It CANNOT go all the way down because there's no where for it to go once it runs into the cutout portion (wheel opening) of the door. The glass is just much bigger than the door can handle.

So no, it's not a child safety feature, its just the way the rear doors are designed. There is absolutely no way around this.