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

DESCRIPTION

The combination meter sub-assembly receives signals from this circuit to adjust the illumination of the meter. The combination meter sub-assembly sets the illumination level based on the user operation of the light control rheostat switch.

Tech Tips


  • The meter illumination level can be adjusted by operating the hazard warning signal switch assembly (light control rheostat switch).


  • The meter illumination dims when the light control switch is turned to the tail, head, or AUTO position at night.


  • Setting the meter illumination to maximum brightness cancels the above dimming of the meter illumination.

WIRING DIAGRAM

A005A7RE04

PROCEDURE


  1. READ VALUE USING GTS (LIGHT CONTROL SWITCH)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / 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 Switch Light control rheostat switch (hazard warning signal switch assembly) / OFF or ON OFF: Light control rheostat switch not pressed -
      ON: Light control rheostat switch pressed
      OK
      The value displayed on the GTS gradually changes as the actual light control rheostat switch operation.

    OK

    REPLACE METER CIRCUIT PLATE Click here

    NG

  2. INSPECT HAZARD WARNING SIGNAL SWITCH ASSEMBLY


    1. A005DQSE07
      Text in Illustration
      *a

      Component without harness connected

      (Light Control Rheostat)

      Remove the hazard warning signal switch assembly Click here.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      2 (CS) - 5 (E) Light control rheostat switch pressed Below 1 Ω
      Light control rheostat switch not pressed 10 kΩ or higher

    NG

    REPLACE HAZARD WARNING SIGNAL SWITCH ASSEMBLY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (COMBINATION METER SUB-ASSEMBLY - HAZARD WARNING SIGNAL SWITCH ASSEMBLY)


    1. Disconnect the L27 combination meter sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L27-26 (TC O) - L57-2 (CS) Always Below 1 Ω
      L57-5 (E) - Body ground Always Below 1 Ω
      L27-26 (TC O) - Body ground Always 10 kΩ or higher

    OK

    REPLACE METER CIRCUIT PLATE Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR