Celica L4-1.8L (1ZZ-FE) (2004)
Brake Light Switch: Testing and Inspection
Stop Light Switch Circuit
STOP LIGHT SWITCH CIRCUIT
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to ECU. When ECU receives this signal, it cancels the cruise control.
A fail-safe function is provided so that the cruise control is canceled normally when there is a malfunction in the stop light signal circuit.
The cancellation occurs when the battery positive voltage is applied to terminal STP-. When the brake is ON, battery positive voltage is applied to
terminal STP- of the ECU via the stop fuse and the stop light switch, and then the ECU turns the cruise control OFF.
Even if the harness connected to terminal STP- has an open circuit, the cruise control will be turned OFF. Also, when the brake is ON, the magnetic
clutch circuit is cut mechanically by the stop light switch, turning the cruise control OFF (See operation of the magnetic clutch).
Wiring Diagram