Headlights always on? -- 2002 Sierra 2500 HD

[omgitsgela]

I inherited my 2002 GMC Sierra 2500 HD Duramax from my father when he passed away this year. It's such a great truck, and I love it. One thing I'm trying to figure out though... the headlights and daytime running lights are always on whenever the truck is running. The switch on the console is in the off position, and all the lights are still on. Doesn't matter what time of day. What's interesting is if I leave the headlight switch in the on position, and then turn off the truck, then the light controls work, and I get warning dings about the lights being left on. But whenever the truck is running, those lights just come on whether I want them to or not.

 

How can I get the lights to stop running constantly, and instead use the switch? What do you folks think is happening here? Thanks!

[Colossus]

The daytime running light sensor which looks like a little r2d2 dome head on the top dash near the windshield.  See if it is covered up or broken. 

 

 

[newdude]

During the day, is it just the DRL that is on?  Or are you getting both the headlights and DRL at the same time?  

[omgitsgela]

12 hours ago, Colossus said:

The daytime running light sensor which looks like a little r2d2 dome head on the top dash near the windshield.  See if it is covered up or broken. 

 

 

There is a sensor on the dashboard, but it doesn't appear broken or covered or anything. Not sure?

[omgitsgela]

1 hour ago, newdude said:

During the day, is it just the DRL that is on?  Or are you getting both the headlights and DRL at the same time?  

All the lights are on whenever the engine is running, regardless of the position of the lighting switch. Headlights and marker lamps.

[omgitsgela]

Okay, I figured this out by accident earlier today. Apparently, if you press the Dome Override button four times in a row, a chime indicates, and the lights will toggle between always on and switch controlled. I've spent WEEKS trying to figure this out and search for the answer.

[Lumpydonut]

On 10/13/2020 at 1:16 AM, omgitsgela said:

Okay, I figured this out by accident earlier today. Apparently, if you press the Dome Override button four times in a row, a chime indicates, and the lights will toggle between always on and switch controlled. I've spent WEEKS trying to figure this out and search for the answer.

 

This was my issue also, glad forums still exist I'd never figure this out elsewhere.

[Roger Decker]

Dude, thank you for this information.  My 2000 Sierra has been going on 5 years now with the headlights always on anytime you start it, and I tried this fix and PRESTO! it worked perfectly.  Not sure how it ever got set that way but glad for this forum to fix it. Thanks again. 

[vucelick]

Unfortunately they revert to always on when you re-start the truck, you have to do the dome override button trick each time you start the truck.