Lighting System Seat Illumination Circuit

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK PERSONAL LIGHT (OPERATION)

PERFORM ACTIVE TEST BY INTELLIGENT TESTER

INSPECT REAR DOME LIGHT ASSEMBLY (REAR SEAT ILLUMINATION)

CHECK HARNESS AND CONNECTOR (OVERHEAD J/B - REAR DOME LIGHT ASSEMBLY)

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)

CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)

CHECK HARNESS AND CONNECTOR (POWER SOURCE)

LIGHTING SYSTEM - Seat Illumination Circuit


DESCRIPTION

The seat illumination can be canceled using the overhead J/B switch.
The turning on and off of the seat illumination is controlled by the main body ECU LH based on various signals received through BEAN communication.
The main body ECU LH includes a MOS-FET (Metal Oxide Semiconductor - Field Effect Transistor) circuit that fades the seat illumination in and out by duty control.
This MOS-FET circuit has an overheat protection function as a fail-safe. If the main body ECU LH becomes excessively hot, the seat illumination turns off and remains off.
Normal operation will resume when the conditions required to turn on the seat illumination are met again.

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit


INSPECTION PROCEDURE

1.CHECK PERSONAL LIGHT (OPERATION)
HINT:
The personal lights and seat illumination share the same power source circuit. Therefore, if none of them come on, inspect the power source circuit first.

  1. Push the personal light switches.

  1. Check that the personal lights come on.

    OK:
    Personal lights come on.


NG
Go to step 7
OK


2.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(s) below in the ACTIVE TEST, and check the operation.

    ACTIVE TEST: Body No. 3 (Main Body ECU LH)
    Item
    		Test Details
    		Diagnostic Note
    Interior Light (Dim) Operation
    		Front and rear seat illumination ON / OFF
    		-
    OK:
    Front and rear seat illumination comes on.

    Result:

    Result
    		Proceed to
    Front seat illumination does not come on
    		A
    Rear seat illumination does not come on
    		B
    Neither front nor rear seat illumination comes on
    		C
    OK
    		D
    HINT:
    If the rear seat illumination comes on normally, but the front seat illumination does not come on, there is an open circuit in the overhead J/B.


A
REPLACE OVERHEAD J/B

B
Go to step 3

C
Go to step 5
D

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

3.INSPECT REAR DOME LIGHT ASSEMBLY (REAR SEAT ILLUMINATION)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit

  1. Remove the rear dome light assembly.

  1. Connect the (+) lead from the battery to terminal 2 and the (-) lead to terminal 5, and then check that the seat illumination comes on.

    OK:
    Seat illumination comes on.


NG
REPLACE REAR DOME LIGHT ASSEMBLY
OK


4.CHECK HARNESS AND CONNECTOR (OVERHEAD J/B - REAR DOME LIGHT ASSEMBLY)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit

  1. Disconnect the R8 rear dome light assembly connector.

  1. Disconnect the R5 overhead J/B connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    R8-2 (ILLB) - R5-4 (ILLB)
    		Always
    		Below 1 Ω
    R8-5 (LILL)- R5-32 (LILL)
    		Always
    		Below 1 Ω
    R8-2 (ILLB) - Body ground
    		Always
    		10 kΩ or higher
    R8-5 (LILL) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE OVERHEAD J/B

5.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit

  1. Disconnect the Q3 main body ECU LH connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    Q3-3 (LGCY) - Body ground
    		Always
    		10 to 14 V


NG
Go to step 6
OK

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

6.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD J/B)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit

  1. Disconnect the Q3 main body ECU LH connector.

  1. Disconnect the R5 overhead J/B connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Q3-3 (LGCY) - R5-12 (CTY)
    		Always
    		Below 1 Ω
    Q3-3 (LGCY) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE OVERHEAD J/B

7.CHECK HARNESS AND CONNECTOR (POWER SOURCE)


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Seat Illumination Circuit

  1. Disconnect the R5 overhead J/B connector.

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    R5-1 (+B1) - Body ground
    		Always
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE OVERHEAD J/B