Circuit/System Description

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The K9 Body Control Module (BCM) provides a low reference, signal, and 5 V reference circuits to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will send a serial data message to the K219 Lighting Control Module to request the stop lamps on. The Lighting Control Module responds by apply battery voltage to the left and right stop lamp control circuits as well as pulse width modulated voltage (PWM) to the center high mounted stop lamp control circuit illuminating the left and right stop lamps and the center high mounted stop lamp.