Principles of Operation: Notes

The Trailer Brake Control (TBC) module is an integrated electronic control device designed to provide variable braking power to the electric-actuated drum brakes on a towed trailer (1 to 4 axles only). The braking energy provided to the trailer is varied with a Pulse Width Modulated (PWM) signal that switches between 0 volts and battery voltage, the higher the duty cycle the more braking power available.

The TBC  module receives information from the stoplamp switch and the PCM. The brake pressure transducer is internal to the ABS module.

The stoplamp switch is mounted on the brake pedal bracket and switches on or off depending on the brake pedal position. The TBC  module receives the stoplamp switch and the brake torque information over the High Speed Controller Area Network (HS-CAN) from the PCM.

The TBC  module receives information through the HS-CAN  . These inputs are from the PCM, the Instrument Panel Cluster (IPC) and the ABS module. The Body Control Module (BCM) also sends ignition state, park lamp status and illumination dimming level data to the TBC  module. The information sent from the TBC  module is passed to the IPC  and is displayed on the message center.

To adjust the gain setting up or down, the TBC  module faceplate provides the driver with control buttons which determine the maximum power output. The TBC  module faceplate also provides a manual control lever to manually apply the trailer brakes, independent of the vehicle brakes, to calibrate the gain setting to the specific trailer loading and road conditions. When the manual control lever is activated with a trailer connected to the vehicle, the trailer stoplamps and the vehicle stoplamps (except the center high mount stoplamp) illuminate. If a trailer is not connected and the manual control lever is activated, the vehicle still illuminates the vehicle stoplamps (except the center high mount stoplamp).