FixVault
Home › Toyota › 2007 › Matrix Base, Standard › Repair and Diagnosis › Electrical › Gauges › Meter › Meter / Gauge System › Operating Light Control Rheostat does not Change Light Brightness › Inspection Procedure

Inspection Procedure

  1. SYSTEM CHECK 

    Result 

    RESULT CHART

    Result Proceed to
    Light illumination level does not change. A
    Light illumination level does not change and tail cancel switch does not operate. A
    Tail cancel switch does not operate. B

    B: Go to step  5

    C: Go to Next Step 

  2. INSPECT LIGHT CONTROL RHEOSTAT (T, GND) 
    Fig 1: Inspecting Light Control Rheostat (T, GND)
    G05237051Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the R8 connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      R8-2 - Body ground Headlight dimmer switch OFF → TAIL Below 1 V → 10 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      R8-7 - Body ground Always Below 1 Ω

    NG: REPLACE LIGHT CONTROL RHEOSTAT 

    OK : Go to Next Step 

  3. INSPECT LIGHT CONTROL RHEOSTAT (TC, LM) 
    Fig 2: Inspecting Light Control Rheostat (TC, LM)
    G05237052Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Check signal waveform.
      1. Remove the light control rheostat with connectors still connected.
      2. Connect the oscilloscope to the terminal C11-35 and body ground.
      3. Check the signal waveform according to the condition(s) in the table below.

        OK 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester connection Condition Specified condition
        R8-5 - Body ground Ignition switch ON Pulse generation (See waveform)

        Waveform (Reference) 

        ITEM CONDITION CHART

        Item Condition
        Tool setting 2V/DIV., 1 ms/DIV.
        Vehicle condition Ignition switch ON
        Fig 3: Identifying Waveform
        G05196119Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        HINT:

        Duty ratio changes as illumination becomes darker ("A" becomes longer).

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

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      R8-3 - R8-4 Tail cancel position (rheostat knob is fully turned up) → Non-tail cancel position 10 kΩ or higher → Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK : Go to Next Step 

  4. CHECK HARNESS AND CONNECTOR (LIGHT CONTROL RHEOSTAT - COMBINATION METER) 
    Fig 4: Checking Harness And Connector (Light Control Rheostat - Combination Meter)
    G05237054Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the C11 and R8 connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      C11-35 - R8-5 Always Below 1 Ω
      C11-7 - R8-3 Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK : REPLACE COMBINATION METER ASSEMBLY 

  5. INSPECT LIGHT CONTROL RHEOSTAT 
    Fig 5: Inspecting Light Control Rheostat
    G05237055Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the R8 connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      R8-3 - R8-4 Tail cancel position (rheostat knob is fully turned up) → Non-tail cancel position 10 kΩ or higher → Below 1 Ω

    NG: REPLACE LIGHT CONTROL RHEOSTAT 

    OK : Go to Next Step 

  6. CHECK HARNESS AND CONNECTOR (LIGHT CONTROL RHEOSTAT - COMBINATION METER) 
    Fig 6: Checking Harness And Connector (Light Control Rheostat - Combination Meter)
    G05237056Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the C11 and R8 connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester connection Condition Specified condition
      C11-7 - R8-3 Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK : REPLACE COMBINATION METER ASSEMBLY 

About FixVault