METER / GAUGE SYSTEM Operating Light Control Rheostat does not Change Light Brightness

DESCRIPTION

When the light control rheostat knob is turned right, the combination meter and vehicle interior illumination will become brighter. When the light control rheostat knob is turned left, the combination meter and vehicle illumination will dim.

WIRING DIAGRAM

B001IBEE05

PROCEDURE


  1. READ VALUE USING GTS (TAIL CANCEL SW, RHEOSTAT VALUE)


    1. Using the GTS, read the Data List Click here.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Tail Cancel SW* Tail cancel switch/OFF or ON OFF: Tail cancel switch off -
      ON: Tail cancel switch on
      Rheostat value Light control rheostat switch input/Min.: 0, Max.: 100 Light control rheostat switch is fully turned right (0) → fully turned left (100) Unit: %

      • *: w/ TAIL Cancel Switch

      OK
      Light brightness can be changed within specified range by manual operation.

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  2. INSPECT TRIP SWITCH (LIGHT CONTROL RHEOSTAT)


    1. Inspect the light control rheostat. (w/o TAIL Cancel Switch)

      A01XFA0E06

      1. Remove the light control rheostat Click here.

      2. Measure the resistance according to the table below.

        Standard Resistance
        for LHD
        Tester Connection Switch Condition Specified Condition
        5 (T) - 1 (E) Always 8 to 12 kΩ
        7 (RV) - 1 (E) Light control rheostat fully turned right → fully turned left Below 100 Ω → 8 to 12 kΩ
        for RHD
        Tester Connection Switch Condition Specified Condition
        8 (T) - 4 (E) Always 8 to 12 kΩ
        6 (RV) - 4 (E) Light control rheostat fully turned right → fully turned left Below 100 Ω → 8 to 12 kΩ

    2. Inspect the light control rheostat. (w/ TAIL Cancel Switch)

      A01XLY7E01

      1. Remove the light control rheostat Click here.

      2. Measure the resistance according to the table below.

        Standard Resistance
        for LHD
        Tester Connection Switch Condition Specified Condition
        5 (T) - 6 (TC) TAIL cancel switch off → on 1 MΩ or higher → Below 1 Ω
        5 (T) - 1 (E) Always 8 to 12 kΩ
        7 (RV) - 1 (E) Light control rheostat fully turned right → fully turned left Below 100 Ω → 8 to 12 kΩ
        for RHD
        Tester Connection Switch Condition Specified Condition
        8 (T) - 7 (TC) TAIL cancel switch off → on 1 MΩ or higher → Below 1 Ω
        8 (T) - 4 (E) Always 8 to 12 kΩ
        6 (RV) - 4 (E) Light control rheostat fully turned right → fully turned left Below 100 Ω → 8 to 12 kΩ

    NG

    REPLACE TRIP SWITCH (LIGHT CONTROL RHEOSTAT) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - TRIP SWITCH [LIGHT CONTROL RHEOSTAT])


    1. Disconnect the G6 combination meter assembly connector.

    2. Disconnect the G16 trip switch (light control rheostat) connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      G6-10 (TC) - G16-6 (TC)* Always Below 1 Ω
      G6-6 (SW1) - G16-5 (T) Always Below 1 Ω
      G6-7 (SW2) - G16-7 (RV) Always Below 1 Ω
      G6-22 (SW3) - G16-1 (E) Always Below 1 Ω
      for RHD
      Tester Connection Condition Specified Condition
      G6-10 (TC) - G16-7 (TC)* Always Below 1 Ω
      G6-6 (SW1) - G16-8 (T) Always Below 1 Ω
      G6-7 (SW2) - G16-6 (RV) Always Below 1 Ω
      G6-22 (SW3) - G16-4 (E) Always Below 1 Ω
      G6-22 (SW3) - G16-4 (E) Always Below 1 Ω

      • *: w/ TAIL Cancel Switch


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK COMBINATION METER ASSEMBLY


    1. Replace the combination meter assembly with a new or normally operating one. Perform an operation inspection.

      OK
      Combination meter assembly operates normally.

    OK

    END (COMBINATION METER ASSEMBLY IS DEFECTIVE)

    NG

    GO TO LIGHTING SYSTEM Click here