I had a wild time with setting up my 2011 Terrain for a 7 pin trailer towing PKG. GM does not supply a towing PKG for electric brakes and the problem came when my installer put the controler in he could not find a dedicated TRIGGER wire due to the module wiring for the Terrains brakes. We ended up taking the trigger feed off of the Chinsil light (Upper Brake lamp) as this is the only wire that activates when brakes are applied. All others are interconnected with signals, 4ways etc. So even when you order the 3500lb PKG the wiring is not enough. If you have any suggestions on how to make it easier for my next truck let me know PLEASE