Principles of Operation

PRINCIPLES OF OPERATION

NOTE: The smart junction box (SJB) is also known as the generic electronic module (GEM).

The trailer lamps and battery charge are supplied power by various relays that are energized to correspond with the exterior lighting functions of the vehicle. If equipped, the vehicle also supplies circuitry to support the installation of an aftermarket trailer brake control module (TBCM) (installed by the customer). The vehicle circuitry only supplies voltage, ground, voltage from the parking lamps circuit (to support backlighting), stoplamp switch input and a controlling circuit to the trailer tow connector. The trailer electric brakes themselves are controlled by the aftermarket TBCM and not the vehicle itself.