I assume the red/black auxilery trailer wire mounts to the unused stud on the front of the fuse box however it still does not work. I read that there may be a dummy fuse..............can anyone tell me which fuse it is. Thank you, Randy.

2007.5 Duramax Dually

On a previous post , someone said it was stud 1 for an 06, you did not say what year your truck is. Charlie

The site wont let me post the file again, but follow this link http://www.dieselplace.com/forum/showthread.php?t=329678

I think you have hooked up the wrong wire. The correct one is under the master cylinder, NOT the one between the fuse box and the fender.

Go here: http://www.dieselplace.com/forum/showpost.php?p=2557997&postcount=1

HTH

On the LMM there are TWO wires under the hood for trailering. BOTH are red with black. One is located between the fender and the fuse box, the other under the master cylinder. The one between the fender and the fuse box is for an after market brake controller and feeds power to the wires under the dash. The one that feeds power to the trailer charge/aux feed is the one below the master cylinder. Brake controller goes to the larger of the two studs and charge/aux feed goes to the smaller of the two studs, you will need an M6 nut for this. A 40amp fuse should already be in place but you might want to check for 12v at the stud to make sure.

You might want to refer to this manual GM Upfitters Electrical Manual – 2008 Light Duty Full Size C/K Trucks (http://www.gmupfitter.com/publicat/2008_BB/08REV_LDCKFST_Elec_D3.pdf) Take a look at page 69 of the PDF or what the manual refers to as page A-57

Thank you guys.....
I found the correct wire with your help. It was under the master cylinder......the other wire between the fender and the fuse box is there also......since I have a factory brake controller so I assume those wires will never do anything?