Headlight Relay Circuit

LIGHTING: LIGHTING SYSTEM: Headlight Relay Circuit
- Headlight Relay Circuit

DESCRIPTION

* The main body ECU receives the light control switch HEAD signal to control the headlight relays. The headlight relays are installed in the power distributor (engine room junction block assembly).

* When the light control switch is in the AUTO position, the main body ECU receives the ambient light level signal from the automatic light control sensor to control the headlight relays.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(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.

(e) Check the operation.

Main Body





OK:

Headlight relays operate (LO-beam headlights illuminate).

NG -- CHECK HARNESS AND CONNECTOR (BATTERY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)

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

2. CHECK HARNESS AND CONNECTOR (BATTERY - ENGINE ROOM JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the 2D engine room junction block assembly connector.





(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.

3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - BODY GROUND)

(a) Disconnect the 2A and 2B engine room junction block assembly connectors.





(b) 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.

4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM JUNCTION BLOCK ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the 2A engine room junction block assembly connector.





(b) Disconnect the 1D instrument panel junction block assembly connector.

(c) 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.

5. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Remove the engine room junction block assembly from the engine room relay block.





(b) Connect a positive (+) lead from the battery to terminal 2D-1.

(c) Connect a negative (-) lead from the battery to terminals 2A-3, 2A-17 and 2B-8.

(d) Measure the voltage according to the value(s) in the table below.

Standard voltage:





NG -- REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY

OK -- REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)