Brake Light Switch: Description and Operation

PURPOSE
Illuminates brake lights and signals ECU when brakes are applied.

LOCATION
Beneath dash adjacent to brake pedal linkage..

OPERATION
The ECU monitors the brake light circuit. As long as the brake pedal is released, the voltage in the brake light circuit is zero. When the brake is applied, voltage in the circuit goes high (approx. battery voltage). The ECU detects the voltage potential and assumes the brake is applied and a deceleration condition exists. This information is used to determine deceleration fuel cut-off operation.