This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have an intermittent "Check Trailer Wiring" or "Service Trailer Brake" message on the Driver Information Center. Technician may find Diagnostic Trouble Code C1114. Technician will inspect and clean the ground wire (normally white wire) connection on the trailer side of the 7-pin connector. Inspect that the wires inside the trailer side connector are clean and securely fastened. If the vehicle's 7-way connector socket terminals are deformed or have excessive wear, it will be necessary to replace the truck side connector from General Motors Customer Care and Aftersales along with the trailer's 7-way connector plug.
