No DRLs

[Crims406]

Hey Everyone, new to the forum and the truck, just picked up a 2011 Sierra 3500HD Duramax Denali. Truck originally from Canada and now in the US. Been working through some of the quirks from the previous owner. One of the things I am trying to track down is why the DRLs never come on. I have read a lot of users trying to disable DRLs, especially Canadian trucks for hunting and such. Thats not me. I just installed some Spec D Projector headlights with C's. That is the reason I would like the DRLS to work. Also I beleive the previous owner had HIDs (just a guess based on the remnants of double sided tape behind headlight housing where i would mount ballansts) and users try to bypass DRLs to extend HID life (from what I read) That being said. Here is what I have checked so far:

 

All the fuses needed for DRLs

Replaced Ambient Light Sensor

Also tested C Lamps with battery and those are working, just not on truck.

Looks like the wiring harness for the headlights has been altered slightly or extended but seems to be correct.

 

I dont know if there is a diode in this year of vehicle- havent checked yet. 

 

Just starting to through it out there and see what sticks, going to start digging into it more shortly but wanted to get the conversation going (good or bad) to see if i can get this figured out. Appreciate the help. Move topic where ever it needs if in wrong section. Few picks of the truck when i got it to where it is now.

 

Edited September 17, 2020 by Crims406
added info

[davester]

I would suggest putting on the parking brake, chocking the wheels, then putting it in drive, making sure the vehicle isn't going to move forward, then start testing power and ground at the bulb connector, then working back.