When i pull my travel trailer the instrument gauge says trailer disconnected and it also says trailer wiring malfunction. I have a 2008 ford f250. 7 Way Diagram - Ajs Truck Trailer Center Trailer Wiring Diagram Trailer Light Wiring Trailer Then my trailer brake systems turns red and blinks. Service trailer brake system 2008 silverado . Take your vehicle to an authorized gm dealer to have the trailer brake system diagnosed and repaired. And it doesnt stop either cant figure out how to shut it off. I have a 2008 chevy 3500 4x4 with the factory trailer brake controller, the service brake system message is displayed and it has a single code in it. The fix is to change t. If this message persists over multiple ignition cycles there is a concern with the trailer brake system. When checking for dtc's, c1112 and/or c1114 will be set in the trailer brake control module (tbcm). So after about 5 months of dealing with the stupid service trailer brake system message on th...