Lexus IS250 IS220d GSE20 ALE20 - LIGHTING

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH ASSEMBLY)

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH)

CHECK HARNESS AND CONNECTOR (COMBINATION SWITCH ASSEMBLY - BODY GROUND)

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH)

LIGHTING SYSTEM - Headlight Signal Circuit

DESCRIPTION

The main body ECU RH receives a HEAD position signal from the combination switch as a backup link. It also receives a signal from the combination switch via the multiplex communication system.


If this link is grounded, the headlights will illuminate.


WIRING DIAGRAM

Lighting System - Headlight Signal Circuit. LIGHTING. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

1.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH ASSEMBLY)
Lighting System - Headlight Signal Circuit. LIGHTING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the J26 combination switch connector.

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    J26-4 (HEAD) - Body groundAlways10 to 14 V
NG
Go to step 4
OK
2.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH)
Lighting System - Headlight Signal Circuit. LIGHTING. Lexus IS250 IS220d GSE20 ALE20

Connect the J26 combination switch connector.

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    J26-4 (HEAD) - Body groundLight control switch is off10 to 14 V
    J26-4 (HEAD) - Body groundLight control switch is in HEAD positionBelow 1 V
NG
Go to step 3
OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3.CHECK HARNESS AND CONNECTOR (COMBINATION SWITCH ASSEMBLY - BODY GROUND)
Lighting System - Headlight Signal Circuit. LIGHTING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the J26 combination switch connector.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    J26-5 (E) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY
4.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU RH - COMBINATION SWITCH)
Lighting System - Headlight Signal Circuit. LIGHTING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the J74 ECU connector.

Disconnect the J26 combination switch connector.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    J74-23 (HEAD) - J26-4 (HEAD)AlwaysBelow 1 Ω
    J74-23 (HEAD) - Body groundAlways10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
REPLACE MAIN BODY ECU RH (COWL SIDE J/B RH)
LEXUS IS250, IS220d / GSE20 ALE20
LIGHTING
Lexus IS250 IS220d GSE20 ALE20
LIGHTING SYSTEM