Stop Lamp Switch
The purpose of the stop lamp switch is to provide the engine control module (ECM) with information indicating whether the brake pedal is depressed or not.
A signal is transmitted to the engine control module (ECM) when the brake pedal is pressed. The engine control module (ECM) disengages the cruise control (if activated). The brake pedal sensor also disengages cruise control.
The stop lamp switch is supplied with power from the ignition switch (terminal 30). When the brake pedal is depressed the switch closes and a high signal (12 V) is transmitted to the engine control module (ECM).
The stop lamp switch can be diagnosed by the engine control module (ECM) and its status (depressed or not) can be read off.
The stop lamp switch is on the pedal box by the brake pedal.