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

DESCRIPTION

The meter CPU receives signals for adjusting illumination on the meter and instrument panel from this circuit. The meter CPU detects the illumination level selected by the user according to the position of the rheostat knob.

Tech Tips


  • The meter illumination level can be adjusted by turning the rheostat.


  • The meter illumination dims when the light control switch is turned to the TAIL or HEAD position at night.


  • Turning the rheostat knob fully clockwise cancels the above dimmer control.

WIRING DIAGRAM

A015ZVPE02

INSPECTION PROCEDURE

PROCEDURE


  1. SYSTEM CHECK

    Result
    Result Proceed to
    Meter illumination does not change when operate the light control rheostat knob A
    Dimmer function cannot be canceled B

    B

    READ VALUE USING INTELLIGENT TESTER (TAIL CANCEL SW) Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (RHEOSTAT VALUE)


    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 / Combination Meter / Data List.

    5. Check the values by referring to the table below.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Light Control Rheostat Light control rheostat/Min.: 0%, Max.: 100% Turn the light control rheostat knob fully counterclockwise (0%) -
      Turn the light control rheostat knob fully clockwise (100%)
      OK
      The value displayed on the intelligent tester gradually changes as the actual rheostat operation.

    NG

    INSPECT LIGHT CONTROL RHEOSTAT Click here

    OK

  3. READ VALUE USING INTELLIGENT TESTER (TAIL CANCEL SW)


    1. Connect the 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 / Combination Meter / Data List.

    5. Check the values by referring to the table below.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Tail Cancel SW Tail cancel switch is OFF or ON OFF: Light control rheostat position is except below. -
      ON: Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON) -
      OK
      Condition displayed on the intelligent tester is the same as the actual light control rheostat knob position.

    NG

    INSPECT LIGHT CONTROL RHEOSTAT Click here

    OK

    REPLACE COMBINATION METER Click here

  4. INSPECT LIGHT CONTROL RHEOSTAT


    1. A01639PE04

      Remove the light control rheostat with the connector still connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (E) - 4 (RV) Turn the rheostat knob fully clockwise 8 to 12 kΩ
      1 (E) - 4 (RV) Rheostat knob is between MIN. and MAX.

      The value changes gradually

      (Between approx. 0 to 8 kΩ)
      1 (E) - 4 (RV) Turn the rheostat knob fully counterclockwise Approx. 0 Ω

    NG

    REPLACE LIGHT CONTROL RHEOSTAT Click here

    OK

  5. CHECK HARNESS AND CONNECTOR (COMBINATION METER - LIGHT CONTROL RHEOSTAT)


    1. A01635XE01

      Disconnect the J34 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J34-14 (ET) - J15-1 (E) Always Below 1 Ω
      J34-9 (ILL+) - J15-3 (T) Always Below 1 Ω
      J34-21 (TR) - J15-4 (RV) Always Below 1 Ω
      J15-1 (E) - Body ground Always 10 kΩ or higher
      J15-3 (T) - Body ground Always 10 kΩ or higher
      J15-4 (RV) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE COMBINATION METER Click here

  6. READ VALUE USING INTELLIGENT TESTER (TAIL CANCEL SW)


    1. Connect the intelligent tester to the DLC3.

    2. Engine switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Combination Meter / Data List.

    5. Check the values by referring to the table below.

      Combination Meter
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Tail Cancel SW Tail cancel switch is OFF or ON OFF: Light control rheostat position is except below. -
      ON: Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON) -
      OK
      Condition displayed on the intelligent tester is the same as the actual light control rheostat position.

    NG

    INSPECT LIGHT CONTROL RHEOSTAT Click here

    OK

    REPLACE COMBINATION METER Click here

  7. INSPECT LIGHT CONTROL RHEOSTAT


    1. A01639PE05

      Remove the light control rheostat with connector still connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (TC) - 3 (T) Turn the light control rheostat knob fully counterclockwise Below 1 Ω
      2 (TC) - 3 (T) Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON) 10 kΩ or higher

    NG

    REPLACE LIGHT CONTROL RHEOSTAT Click here

    OK

  8. CHECK HARNESS AND CONNECTOR (COMBINATION METER - LIGHT CONTROL RHEOSTAT)


    1. A01635XE03

      Disconnect the J34 connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      J34-8 (TC) - J15-2 (TC) Always Below 1 Ω
      J15-2 (TC) - Body ground Always 10 kΩ or higher
      J34-9 (ILL+) - J15-3 (T) Always Below 1 Ω
      J15-3 (T) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE COMBINATION METER Click here