Well decided to take some pictures and help anyone out on installing a aftermarket trailer brake controller on these new trucks. My dad's truck is a 2014 GMC Sierra SLT that has every other option except for the integrated trailer brake controller. When I called around to the local dealers I got no help about if they could install the factory switch and harness so went the aftermarket route. Needless to say not much info on that either except for one post on the GM-Trucks forum. Anyways here are some pictures and some info on how to install a aftermarket trailer brake controller on trucks not originally equipped with one...

First off your gunna need a harness from controller to truck. The one I used was for a 99-06 truck that I had to modify just a bit but clips in solid. Also the junction box we are gonna plug into is right under the driver side dash near the emergency brake. Just take the cover off and you will see where you have to plug into...









Next your gonna have to de pin and trim off the last two terminals to make it a 4 prong connector. Also your connector like mine did might have a little specific slot molded into it. Just trim to fit.





Next re pin your connector to your controller spec, here's a pic of the terminals in the truck...





Once the connector is made plug into the truck junction box and your ready to go. Just plug the harness into your aftermarket trailer brake controller and mount it...



Hopefully this helps anyone trying to do this.

 

Nice write up!

 

Very good and useful right up