Daytime Running Light Relay Circuit

LIGHTING: LIGHTING SYSTEM: Daytime Running Light Relay Circuit

Daytime Running Light Relay Circuit

DESCRIPTION

The main body ECU controls the DRL NO. 4 relay. The DRL NO. 4 relay connects the daytime running light relay and the headlight during operation. The daytime running light relay controls the illuminance of the headlight accordingly.

WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: Check if the headlight (low beam and high beam) is normal before performing the following procedure.

PROCEDURE

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

Main body ECU





OK:
Headlight (High beam) comes on.
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

2. CHECK DAYTIME RUNNING LIGHT RELAY




(a) Measure the voltage of the relay connector.
Standard voltage:






NG -- CHECK WIRE HARNESS (DAYTIME RUNNING LIGHT RELAY - BODY GROUND)
OK -- Continue to next step.

3. CHECK WIRE HARNESS (ECU - BATTERY)




(a) Disconnect the B6 ECU connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. CHECK WIRE HARNESS (DAYTIME RUNNING LIGHT RELAY - BODY GROUND)




(a) Disconnect the D2 relay connector.
(b) Measure the resistance of the wire harness side connector.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. CHECK WIRE HARNESS (DAYTIME RUNNING LIGHT RELAY - BATTERY)




(a) Disconnect the D2 relay 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.

6. CHECK DRIVER SIDE JUNCTION BLOCK (MAIN BODY ECU)




(a) Measure the voltage of the connector.
Standard voltage:






NG -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK - DAYTIME RUNNING LIGHT RELAY)