Headlight Control Relay Circuit

Headlight Control Relay Circuit

CIRCUIT DESCRIPTION
When the theft deterrent system is activated, it causes the transistor in the ECU to switch ON and OFF at approximately 0.4 sec. intervals. This switches the headlight control relay ON and OFF, thus flashing the headlights (See the wiring diagram).

In this condition, if any of the following operations is done, the transistor in the ECU goes OFF and the headlight control relay switches OFF, thus stopping the headlights flashing:

1. Unlock the front LH or RH door with a key.
2. Turn the ignition switch to ON position.
3. Unlock the doors with the wireless door lock control system.
4. Wait for approximately 60 seconds.

Wiring Diagram:

Step 1 - 2:

INSPECTION PROCEDURE

HINT: The flow chart shown is based on the premise that the headlights light up normally whenever the light control switch is operated. If headlight operation is not normal when the light control switch is operated, proceed to troubleshooting.

In case of using the LEXUS hand-held tester, start the inspection from step 1 and in case of not using the LEXUS hand-held tester, start from step 2.