Anyone know what the replacement part number is? I'm struggling to find this.

 

Welcome to the forum. Should be in your owner's manual, otherwise someone smart will chime in soon!

 

It may be that the LED strip is built into the headlamp housing and can only be replaced by replacing the entire housing. This is all I could find:

http://www.gmpartsdirect.com/auto-pa...umber=22783093

and I don't see a part number for the LED DRL.

Hopefully you're still under warranty. The headlamp housing for HID are super crazy expensive.