Lighting System Headlight Relay Circuit

Body Electrical. Lexus Is250, Is220D. Gse20 Ale20
Lighting. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

PERFORM ACTIVE TEST BY INTELLIGENT TESTER

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

INSPECT HEAD LP RELAY

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

CHECK HARNESS AND CONNECTOR (HEADLIGHT (LOW LH OR LOW RH) - BATTERY AND BODY GROUND)

CHECK HARNESS AND CONNECTOR (HEADLIGHT (LOW LH OR LOW RH) - HEAD LP RELAY)

LIGHTING SYSTEM - Headlight Relay Circuit


DESCRIPTION

The headlight relay is turned on by operating the headlight switch.
When the theft deterrent system is activated, it causes the ECU to turn the headlight 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 headlight relay off to stop the headlight from flashing:
  1. Unlock the driver door with a key.
  2. Turn the engine switch on (ACC or IG).
  3. Unlock the doors with the wireless door lock control system.

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit


Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit


INSPECTION PROCEDURE

1.PERFORM ACTIVE TEST BY INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Turn the intelligent tester main switch on.

  1. Select the item below in the ACTIVE TEST and then check the relay operation.

    ACTIVE TEST: Body (Main Body ECU RH)
    Item
    		Test Details
    		Diagnostic Note
    Headlight Relay
    		Headlight relay ON / OFF
    		-
    OK:
    Headlight assembly (low) illuminates.


OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG


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

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

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

  1. Measure the resistance of the fuses.

    Standard resistance:
    Below 1 Ω


NG
REPLACE FUSE
OK


3.INSPECT HEAD LP RELAY


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit

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

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (When battery voltage is applied to terminals 1 and 2)


NG
REPLACE HEAD LP RELAY
OK


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


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit

  1. Disconnect the RL main body ECU RH connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    RL-7 (HRLY) - Body ground
    		Always
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit

  1. 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 and resistance according to the value(s) in the table below.

      Standard voltage:
      Tester Connection
      		Condition
      		Specified Condition
      B12-17 (LO) - Body ground
      		Turn the light control switch to the ON (HEAD) position.
      		10 to 14 V
      Standard resistance:
      Tester Connection
      		Condition
      		Specified Condition
      B12-16 (E) - Body ground
      		Always
      		Below 1 Ω


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit

  1. 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 and resistance according to the value(s) in the table below.

      Standard voltage:
      Tester Connection
      		Condition
      		Specified Condition
      B2-17 (LO) - Body ground
      		Turn the light control switch to the ON (HEAD) position.
      		10 to 14 V
      Standard resistance:
      Tester Connection
      		Condition
      		Specified Condition
      B2-16 (E) - Body ground
      		Always
      		Below 1 Ω


OK
REPLACE HEADLIGHT ASSEMBLY (LOW LH OR LOW RH)
NG


6.CHECK HARNESS AND CONNECTOR (HEADLIGHT (LOW LH OR LOW RH) - HEAD LP RELAY)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Headlight Relay Circuit

  1. Check the harness and the connectors between the headlight (Low LH or Low RH) and the HEAD LP relay.

    1. Disconnect the B12 light connector.

    2. Remove the HEAD LP relay from the engine room No. 1 relay block.

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

      Standard resistance:
      Check for open:
      Headlight Assembly
      		Tester Connection
      		Specified Condition
      LH
      		B12-17 (LO) - HEAD LP relay terminal (3)
      		Below 1 Ω
      RH
      		B2-17 (LO) - HEAD LP relay terminal (3)
      		Below 1 Ω
      Check for short:
      Headlight Assembly
      		Tester Connection
      		Specified Condition
      LH
      		B12-17 (LO) or HEAD LP relay terminal (3) - Body ground
      		10 kΩor higher
      RH
      		B2-17 (LO) or HEAD LP relay terminal (3) - Body ground
      		10 kΩor higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

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