Headlight Signal Circuit

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

DESCRIPTION

The main body ECU receives a headlight switch information signal from the light control switch, and illuminates the headlight low beam.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (HEADLIGHT)

(a) Operate the Techstream according to the steps on the display and select "Active Test".

Main Body





OK:

Headlight low beam turns on/turns off.

NG -- INSPECT FUSE (HEAD LL, HEAD RL)

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

2. INSPECT FUSE (HEAD LL, HEAD RL)

(a) Remove the HEAD LL and HEAD RL fuses 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.

3. INSPECT HEADLIGHT RELAY (HEAD LO)

(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 (HEADLIGHT RELAY (HEAD LO) - BATTERY)

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





(b) Measure the voltage 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 - HEADLIGHT RELAY (HEAD LO) AND BODY GROUND)





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

(b) for LH:

(1) Disconnect the A3 headlight connector.

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

Standard Resistance:





(c) for RH:

(1) Disconnect the A12 headlight connector.

(2) 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 HEADLIGHT (LOW BEAM)

(a) Disconnect the 2B ECU connector.





(b) Using a service wire, connect terminal 2B-18 (HRLY) on the wire harness side and body ground.

(c) Check that the headlight low beam illuminates.

OK:

Headlight low beam illuminates.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (HEADLIGHT RELAY - MAIN BODY ECU)

OK -- REPLACE MAIN BODY ECU