Headlights always on no DRL

[baxternick]

My wife wrecked her 02 yukon a month ago. I just put a new clip on the front and now the headlights are always on when you start the truck. I have to hit the override button 4 times to turn them off during the day but the Day time running lights never come on. I rotated the DRL relay with a new one and checked all fuses associated with front lights. Anything I am missing here? Is there any sensors up front I could have to replace that were on the core support? I also checked the leads at the 4144 bulbs and there is no power so I know its not the bulbs. Plus the headlights always on throws me for a loop.

 

Thanks in advance for taking time to help!

[KMGZ400]

go look at your dash directly in the center about 1 to 2 inches from the windsheild there should be a black dome thing sticking out of the dash. if you see a hole, it means the dome fell down into the hole and its dangling around in your dash. you have to take your dash apart to get the dome out unless you can reach it with tweezers or something

 

edit

 

just looked and its not directly in the center but its right next to a vent. this is a shitty pic but if you look the the reflection in the windshield next to the EZPASS you can see a round black dome

 

[baxternick]

Checked the sensors. They are both intact in the dash.

[KMGZ400]

the light switch itself could have gone bad.. if you know anyone else with another 99-02 GMT800 you could swap switches and see if thats the culprit

[bossier62guy]

You could also try shining a bright light directly at the sensor.....it may be heading south. I do believe the sensor sends a signal directly to the BCM.

[txab]

Checked the sensors. They are both intact in the dash.

 

 

There is only one ambient light sensor. It is bad, replace it.

 

Procedure

 

 

[bossier62guy]

Before I torn the dash apart I'd remove the radio and hvac control and see if there's any possible way to reach that sensor. I know I've seen it hanging there w/ my radio removed before but I'm just not sure if you can get your hand in those tight spaces. Good luck w/ that....

[txab]

Before I torn the dash apart I'd remove the radio and hvac control and see if there's any possible way to reach that sensor. I know I've seen it hanging there w/ my radio removed before but I'm just not sure if you can get your hand in those tight spaces. Good luck w/ that....

 

 

The dash removal is simple and quick. Removing the radio and HVAC is BS. I can do it in 20 minutes

[bossier62guy]

Well you must be the man Tex.....sorry you think my idea is bullshit but not everyone wants take the dash apart. I'll refrain from further advice since you seem to have it all covered!

[txab]

I apologize for the way it came out. For replacement, it's easier and requires not much additional time than your suggested method. It looks worse than it is. I've seen to many people use the radio/HVAC method only to end up pulling the cover. If you have small hands it can work if your sensor has just dropped down and needs to be pushed back up.

[baxternick]

I have been working in the mobile electronic field/12 volt repair for 12+ years now. So dash removal is no problem. Any chance it's the BCM?

Thanks guys!

[txab]

There is always a chance. But 9 times out of 10 it's the ambient light sensor. The ambient sensor can also be removed and bypassed so as disable DRLs and make your headlights manual. It involves installing a resistor, IIRC

[baxternick]

There are two sensors in the center dash area. Is the light on the right or left? I assume the other is a dummy, or for climate control...

[txab]

The light sensor should look like the one pictured above. I believe it will be in the same location. It's pretty cheap. '04 and up use a more expensive one