Installing 12-Volt Accessory Trailer Power Feed Fuse in 2010 GMC Sierra

Updated 09/11/2025 | Published 06/27/2015

Question:

While I am waiting for the P3 I purchased from you Ive been checking for what I might need for the install. My truck , a 2010 Sierra, came with a factory installed 7 way and I found the wire bundle under the dash that was described in your video. I also found the 2 red wires under the hood. I was looking at the fuse diagram on the fuse box and noticed that stud 2 had a 30amp fuse but stud 1 was empty. Im assuming they are referring to the 2 studs that I will be making connections to. My question is: do I need a 40amp fuse for stud1? Thank you

asked by: Joe B

Expert Reply:

You will indeed need to install a 40 amp fuse in position 68 to activate stud 1 that powers the 12-volt accessory power circuit to the trailer connector. If there isn't already a wire connected to stud 1, you'll need to locate the red wire with the ring terminal located under the brake booster and attach it to stud 1.I've edited a photo for you showing where the wire is located, and I'll also link you to our FAQ article about installing a brake controller on your truck.

expert reply by: Mike L