Brake Light Switch
The task of the brake light switch is to provide the Engine Control Module (ECM) with information about the position of the brake pedal.
When the brake pedal is depressed, a signal is sent to the Engine Control Module (ECM) that switches off cruise control (if it is activated).
The brake light switch is supplied with power from the relay/fusebox engine compartment (KL30) and when the brake pedal is depressed the switch closes and a high signal (12 V) is transmitted to the Engine Control Module (ECM).
The Engine Control Module (ECM) can diagnose the brake light switch. The status of the switch can be read using the diagnostic tool.
The brake light switch is on the pedal box by the brake pedal.