Headlight Relay Circuit

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

DESCRIPTION

The HEAD LP relay is operated by the main body ECU RH when it receives a signal via BEAN from the windshield wiper switch assembly (light control switch).

A backup line is also provided to enable headlight operation if there is a communication malfunction. The line runs between the windshield wiper switch assembly (light control switch) and main body ECU RH.

When the theft deterrent system is activated, it causes the ECU to turn the HEAD LP relay on and off repeatedly at approximately 0.25 second intervals to flash the headlights.

In this condition, if any of the following operations is performed, the ECU turns the HEAD LP relay off to stop the headlight from flashing:

* Unlock the driver door with a key.

* Turn the engine switch on (ACC or IG).

* Unlock the doors with the wireless door lock control system.

WIRING DIAGRAM









INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Body / Active Test.

(e) Check the operation.

Body (Main Body ECU RH)





OK:

Headlight assembly (low) illuminates.

NG -- INSPECT FUSE (H-LP L LWR, H-LP R LWR)

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2. INSPECT FUSE (H-LP L LWR, H-LP R LWR)

(a) Remove the H-LP L LWR fuse from the engine room No. 2 relay block.

(b) Remove the H-LP R LWR fuse from the engine room No. 2 relay block.

(c) Measure the resistance of the fuses.

Standard resistance:

Below 1 Ohms

NG -- REPLACE FUSE
OK -- Continue to next step.

3. INSPECT HEAD LP RELAY

(a) Remove the HEAD LP relay from the engine room No. 1 relay block.





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

Standard resistance:





NG -- REPLACE HEAD LP RELAY
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - BATTERY)

(a) Disconnect the RL main body ECU RH 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.

5. CHECK HARNESS AND CONNECTOR (HEADLIGHT (LOW LH OR LOW RH) - BATTERY)

(a) Check the wire harness between the headlight (Low LH) and battery, and the headlight (Low LH) and body ground.

(1) Disconnect the B12 headlight connector.

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

Standard voltage:





(b) Check the wire harness between the headlight (Low RH) and battery, and the headlight (Low RH) and body ground.

(1) Disconnect the B2 headlight connector.

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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE MAIN BODY ECU RH (COWL SIDE J/B RH)