Headlight Relay Circuit

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

DESCRIPTION

The main body ECU receives a light control switch HEAD signal from the headlight dimmer switch assembly, and turns the low beam headlights on. The headlight relay is installed in the power distributor (engine room J/B assembly).

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch on (IG).

(c) Turn Techstream on.

(d) Select the following menu items: Body Electrical / Main Body / Active Test.

(e) Check that the relays operate.

Main Body:





OK:

Headlight relays operate. (LO-beam headlights illuminate.)

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

2. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

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





Standard voltage:





OK -- INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY
NG -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (BATTERY - ENGINE ROOM J/B ASSEMBLY)

(a) Disconnect the 1G engine room J/B 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.

4. INSPECT ENGINE ROOM J/B BLOCK ASSEMBLY

(a) Reconnect the 1G engine room J/B assembly connector.

(b) Disconnect the 1D engine room J/B assembly connector.





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

Standard voltage:





NG -- REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY (POWER DISTRIBUTOR)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (ENGINE ROOM J/B ASSEMBLY - INSTRUMENT PANEL J/B ASSEMBLY)

(a) Reconnect the 1D engine room J/B assembly connector.

(b) Disconnect the ID instrument panel J/B assembly connector.





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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

6. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Remove the H-LP (RL) fuse and H-LP (LL) fuse from the engine room J/B assembly.





(b) Measure the voltage between the loading slot of each fuse and body ground.

Standard voltage:





NG -- REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY (POWER DISTRIBUTOR)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (FUSE - BODY GROUND)