LIGHTING SYSTEM Seat Illumination Circuit

DESCRIPTION

The seat illumination can be canceled using the overhead junction block switch.

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

A0161C0E05

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK PERSONAL LIGHT (OPERATION)

    Tech Tips

    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.

    2. Check that the personal lights come on.

      OK
      Personal lights come on.

    NG

    CHECK HARNESS AND CONNECTOR (POWER SOURCE) Click here

    OK

  2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Body No. 3 / Active Test.

    5. Check the operation.

      Body No. 3 (Main Body ECU LH)
      Tester Display Test Part Control Range 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

      Tech Tips

      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 junction block.


    A

    REPLACE OVERHEAD JUNCTION BLOCK Click here

    B

    INSPECT SPOT LIGHT ASSEMBLY (REAR SEAT ILLUMINATION) Click here

    C

    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD JUNCTION BLOCK) Click here

    D

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

  3. INSPECT SPOT LIGHT ASSEMBLY (REAR SEAT ILLUMINATION)


    1. A01624HE05

      Remove the spot light assembly.

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

      OK
      Seat illumination comes on.

    NG

    REPLACE SPOT LIGHT ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (OVERHEAD JUNCTION BLOCK - SPOT LIGHT ASSEMBLY)


    1. A0162G1E03

      Disconnect the R8 spot light assembly connector.

    2. Disconnect the R5 overhead junction block connector.

    3. 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 JUNCTION BLOCK Click here

  5. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD JUNCTION BLOCK)


    1. A0160UEE05

      Disconnect the Q3 main body ECU LH connector.

    2. 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 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD JUNCTION BLOCK) Click here

    OK

    REPLACE MAIN BODY ECU LH (COWL SIDE JUNCTION BLOCK LH)

  6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - OVERHEAD JUNCTION BLOCK)


    1. A0160ANE05

      Disconnect the Q3 main body ECU LH connector.

    2. Disconnect the R5 overhead junction block connector.

    3. 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 JUNCTION BLOCK Click here

  7. CHECK HARNESS AND CONNECTOR (POWER SOURCE)


    1. A01631RE01

      Disconnect the R5 overhead junction block connector.

    2. 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 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE OVERHEAD JUNCTION BLOCK Click here