Headlight Signal Circuit
LIGHTING (EXT): LIGHTING SYSTEM: Headlight Signal Circuit
- Headlight Signal Circuit
DESCRIPTION
The main body ECU receives a headlight Lo 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) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Main Body / Active Test / Headlight Relay
(e) Check that the headlight (low) turn on/off.
Main Body ECU
OK:
Headlight low beams turn on/off.
NG -- INSPECT FUSE (HEAD LL, HEAD RL)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Exterior Lighting System
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:
(c) Reinstall the HEAD LL and HEAD RL fuses.
NG -- REPLACE FUSE
OK -- Continue to next step.
3. INSPECT HEADLIGHT (LOW) BULB
(a) Temporarily replace the headlight (low) bulb with a new or normally functioning one Disassembly.
(b) Check that the headlight (low) turn on.
OK:
Headlight (low) turn on.
NG -- CHECK HARNESS AND CONNECTOR (HEADLIGHT LOW BULB - HEAD RELAY)
OK -- END
4. CHECK HARNESS AND CONNECTOR (HEADLIGHT LOW BULB - HEAD RELAY)
(a) for LH:
(1) Disconnect the A12 headlight (low) LH connector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(3) Reinstall the headlight (low) LH connector.
(b) for RH:
(1) Disconnect the A13 headlight (low) RH connector.
(2) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(3) Reinstall the headlight (low) RH connector.
NG -- INSPECT HEADLIGHT RELAY (HEAD)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (HEADLIGHT LOW BULB - BODY GROUND)
5. INSPECT HEADLIGHT RELAY (HEAD)
(a) Remove the HEAD relay from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Reinstall the HEAD relay.
NG -- REPLACE HEAD RELAY
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (HEAD RELAY - BATTERY)
(a) Remove the HEAD relay from the engine room relay block.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(c) Reinstall the HEAD relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (HEAD RELAY - HEADLIGHT LOW BULB)
(a) Remove the HEAD relay from the engine room relay block.
(b) for LH:
(1) Disconnect the A12 headlight (low) LH connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(3) Reinstall the headlight (low) LH connector.
(c) for RH:
(1) Disconnect the A13 headlight (low) RH connector.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(3) Reinstall the headlight (low) RH connector.
(d) Reinstall the HEAD relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HEADLIGHT (HEADLIGHT RELAY - MAIN BODY ECU)
(a) Disconnect the DB main body ECU connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
(c) Reconnect the main body ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MAIN BODY ECU