To all the GMC guys...I've got the fix! Firstly, just want to thank @spurshot for inspiring me to put this into motion. Ever since I saw the 14+ GMC's, I thought to myself hmm...I wonder if it's possible to make those bright DRL LED's run the same at night.
I probably wouldn't have dived into this if it wasn't for Spurshot's How-To on the Fogs w/Highs as I used the same idea with this. So here it is, using the same 1N4004 diodes:
BCM X4 (Black Connector) Pin 1 to Pin 7 Pin 2 goes to Pin 7 on BCM X5 (Brown Connector)
See pictures below for the schematics.
BEFORE & AFTER
And yes...I'm putting in HID's this weekend. Just picked up a 2015 Denali CC 6.2L/8spd in exchange for my 2014 High Country and the mods are still in progress! Enjoy