erikankrom

I haven't read through all 11 pages of this forum, but I did find the diagrams and instructions very helpful, with one additional point of clarification. There are TWO gray wires (without stripes) on the 2015 GMC Sierra 1500 SLT Crew. One is around 20-22 gauge wire, the other is around 18-20 gauge. The one you want is the thicker of the two. It may be buried in the bundle of wires, just keep looking for it. If you want to be sure, use a computer safe circuit tester. Unfortunately, I didn't have one on hand, so I learned the hard way.