Headlight Relay Circuit

LIGHTING (EXT): LIGHTING SYSTEM: Headlight Relay Circuit
- Headlight Relay Circuit

DESCRIPTION

The daytime running light relay receives the light control switch HEAD signal and the ambient light level signal from the automatic light control sensor to control the headlight relay.

HINT
If only a low beam headlight bulb on one side does not illuminate, inspect the bulb, fuse, or wire harness related to the bulb.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT FUSE (H-LP MAIN)

(a) Remove the H-LP MAIN fuse from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPLACE FUSE
OK -- Continue to next step.

2. INSPECT ENGINE ROOM RELAY BLOCK

(a) Install the H-LP MAIN fuse to the engine room relay block.

(b) Remove the H-LP LH LO fuse and H-LP RH LO fuse from the engine room relay block.





(c) Measure the voltage between the loading slot of each fuse and body ground.

Standard Voltage:





NG -- INSPECT HEADLIGHT RELAY (H-LP)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FUSE - BODY GROUND)

3. INSPECT HEADLIGHT RELAY (H-LP)

(a) Remove the headlight relay from the engine room relay block.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPLACE HEADLIGHT RELAY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (BATTERY - HEADLIGHT RELAY)

(a) Measure the voltage on the relay block side according to the value(s) in the table below.





Standard Voltage:





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

5. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY - FUSE)

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





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

6. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY - DAYTIME RUNNING LIGHT RELAY)

(a) Disconnect the E42 daytime running light relay connector.





(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Exterior Lighting System