Trailer Brake Power Control Module
WARNING: This page is about a different car, the 2020 Chevrolet Silverado 1500. However, it is still accessible from the selected car via links, so may be relevant.
The K133 Trailer Brake Power Control Module (TBPM) is a solid state power switching module that supplies power to the trailer brakes at the input command duty cycle. Diagnostic messages are sent from the TBPM to the BSCM on a dedicated LIN bus.