Headlight Relay Circuit

LIGHTING: LIGHTING SYSTEM: Headlight Relay Circuit

Headlight Relay Circuit

DESCRIPTION

The headlight relay is turned ON by operating the headlight switch.
When the theft deterrent system is activated, it causes the ECU to turn the headlight relay on and off repeatedly at approximately 0.25 second intervals to flash the headlights.
In this condition, if any of the following operations is performed, the ECU to turns the headlight relay off to stop the headlight from flashing:

- Unlock the driver door with a key.
- Turn the engine switch on (ACC) or on (IG).
- Unlock the doors with the wireless door lock control system.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Select the ACTIVE TEST, use the Techstream to generate a control command, and then check that the headlight assembly (low) illuminates.

Body (Multiplex network body ECU)





OK:
Headlight assembly (low) illuminates.
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.
2. INSPECT FUSE (H-LP L LWR, H-LP R LWR)
(a) Remove the H-LP L LWR fuse from the engine room No. 2 relay block.
(b) Remove the H-LP R LWR fuse from the engine room No. 2 relay block.
(c) Measure the resistance of the fuses.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT HEAD LP RELAY





(a) Remove the HEAD LP relay from the engine room No. 1 relay block.
(b) Measure the resistance of the HEAD LP relay.
Standard resistance:






NG -- REPLACE HEAD LP RELAY
OK -- Continue to next step.
4. CHECK WIRE HARNESS (COWL SIDE JUNCTION BLOCK RH - BATTERY)





(a) Disconnect the DL junction block connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
5. CHECK WIRE HARNESS (HEADLIGHT (LOW LH OR LOW RH) - BATTERY AND BODY GROUND)





(a) Check the wire harness between the headlight (Low LH) and battery, and the headlight (Low LH) and body ground.
(1) Disconnect the B11 light connector.
(2) Turn the light control switch to the ON (HEAD) position.
(3) Measure the voltage and resistance of the wire harness side connector.
Standard voltage:






Standard resistance:










(b) Check the wire harness between the headlight (Low RH) and battery, and the headlight (Low RH) and body ground.
(1) Disconnect the B2 light connector.
(2) Turn the light control switch to the ON (HEAD) position.
(3) Measure the voltage and resistance of the wire harness side connector.
Standard voltage:






Standard resistance:






OK -- REPLACE HEADLIGHT ASSEMBLY (LOW LH OR LOW RH)
NG -- Continue to next step.
6. CHECK WIRE HARNESS (HEADLIGHT (LOW LH OR LOW RH) - HEAD LP RELAY)





(a) Check the harness and the connectors between the headlight (Low LH or Low RH) and the HEAD LP relay.
(1) Disconnect the B11 light connector.
(2) Remove the HEAD LP relay from the engine room No. 1 relay block.
(3) Measure the resistance of the wire harness side connectors.
Standard resistance (Check for open):






Standard resistance (Check for short):






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE