what do I need to do with a short electical harness that was included with my GM tow pkg that I got installed after the fact? , its supposed to be for electic brakes?

 

Is it one black wire with a cap on the end if so its for the elect trailer brakes.

 

under the dast to the left of your brake pedal, theres a covered black box, the cover is held on with 1 screw, remove it and the cover, plug the harness into the correct plug, ithe cover has a diagram. You should also have a fuse to install in the main fuse panel underhood. If you don't go to any part store and get a 40A j-case fuse, it plugs into Stud #1, it may be covered by a red plug

 

You will need to buy a trailer brake controller to attach the harness to. Then install it as 03NHSilvy suggested. You only need to install it if the trailer you haul has electric brakes or if you intend to haul a trailer with electric brakes in the future.

 

These guys got it for ya.

 

whats a trailer brake controler? where do you get one? I'm assuming its some kinda electric control box like a snowplow controler that you have to mount and then use when needed? I looked at the back of the round 7 pin connector on the hitch mount and there is a extra wire with a plastic cap on it hanging off the main harness that gets plugged in from the truck chassis harness to the round connecter??

 

a brake controller is a means of controlling the power to the electric brakes on a trailer. It lets you select how much power to send to the brakes (based on the load in the trailer) And I think you can make it so the trailer brakes operate on a delay from when you press your trucks brake pedal. That extra wire is for if you have a cap with a 3rd brake light, that will power it. Check out some of the RV sites for good towing info, as towing doesn't seem to be a main focus here