Trailer Brake Power Control Module
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2016 GMC Sierra 3500 HD, 2016 GMC Sierra 2500 HD, 2016 GMC Sierra 1500, 2016 Chevrolet Silverado 3500 HD, and 2016 Chevrolet Silverado 2500 HD. 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 CCM on a dedicated LIN bus.