Circuit/System Description

WARNING: This page is about a different car, the 2017 Cadillac ATS. However, it is still accessible from the selected car via links, so may be relevant.

The trailer lighting control module is supplied with battery voltage as well as ignition voltage from the rear body fuse block and is permanently grounded. For lighting operation, the trailer lighting control module receives serial data messages from the body control module (BCM) indicating what lamps have been activated on the vehicle. The trailer lighting control module responds by applying voltage to the appropriate control circuits for the requested lamps illuminating the lamps on the attached trailer. To prevent a lighting failure, the trailer lighting control module counts and stores the number of short circuits that have occurred during system operation. These short circuits can occur on the vehicles trailer lighting circuits as well as the circuits on the operators trailer wiring. When the trailer lighting control module internal counter reaches 60% of the maximum allowed short circuits, a DTC is set as present.