Headlight Relay Circuit
LIGHTING: LIGHTING SYSTEM: Headlight Relay Circuit
Headlight Relay Circuit
DESCRIPTION
The main body ECU controls H-LP relay and DIM relay when signals are received from the combination switch.
WIRING DIAGRAM
INSPECTION PROCEDURE
PROCEDURE
1. PERFORM ACTIVE TEST USING TECHSTREAM (HEADLIGHT)
(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 turns on.
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.
2. CHECK WIRE HARNESS (ECU - BODY GROUND)
(a) Disconnect the B7 ECU connector.
(b) Using a service wire, connect B7-20 (HRLY) of the wire harness side and body ground.
OK:
Headlight (Low beam) turns on.
NG -- CHECK WIRE HARNESS (ECU - BATTERY)
OK -- Continue to next step.
3. CHECK WIRE HARNESS (ECU - BODY GROUND)
(a) Disconnect the B7 ECU connector.
(b) Using a service wire, connect B7-20 (HRLY) of the wire harness side and body ground.
(c) Using a service wire, connect B7-2 (DRL/DIM) of the wire harness side and body ground.
OK:
Headlight (High beam) turns on.
NG -- CHECK WIRE HARNESS (ECU - BATTERY)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. CHECK WIRE HARNESS (ECU - BATTERY)
(a) Disconnect the B7 ECU connector.
(b) Measure the voltage of the wire harness side connector.
Standard voltage:
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK - BATTERY)
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR (EACH HEADLIGHT (LOW BEAM) CIRCUIT)
5. CHECK WIRE HARNESS (ECU - BATTERY)
(a) Disconnect the B7 ECU connector.
(b) Using a service wire, connect B7-20 (HRLY) of the wire harness side and body ground.
(c) Measure the voltage of the wire harness side connector.
Standard voltage:
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK)
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR (EACH HEADLIGHT (HIGH BEAM) CIRCUIT)