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 E91 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