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Home >> Scion >> 2005 >> xA Standard >> Repair and Diagnosis >> Electrical >> Gauges >> Combination Meter >> Operating Light Control Rheostat Does Not Change Light Brightness >> Inspection Procedure

Inspection Procedure

  1. CHECK LIGHT CONTROL RHEOSTAT 
    1. Check that the illumination of the radio and player, center cluster module switch, etc. can be adjusted by the rheostat.

      OK : The illumination can be adjusted. 

      1. NG : Go to step   6 
      2. OK : GO TO NEXT STEP. 
  2. INSPECT COMBINATION METER ASSY 
    1. Disconnect the C10 connector.
    2. Measure the voltage between the terminal and body ground.

      Standard: 

      COMBINATION METER

      Tester Connection Condition Specified Condition
      C10-12 - Body ground Ignition switch is ON and lamp control switch is at TAIL or HEAD 10 to 14 V
      Fig 1: Inspecting Combination Meter Assembly
      G03196865Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION SWITCH - COMBINATION METER ASSY) 
    2. OK : GO TO NEXT STEP. 
  3. CHECK HARNESS AND CONNECTOR (LIGHT CONTROL RHEOSTAT - COMBINATION METER ASSY) 
    1. Disconnect the C11 and R6 connectors.
    2. Measure the resistance between the terminals.

      Standard: 

      LIGHT CONTROL RHEOSTAT - COMBINATION METER

      Tester Connection Specified Condition
      C11-7 - R6-3 Below 1 Ω
      Fig 2: Checking Harness And Connector (Light Control Rheostat - Combination Meter)
      G03196866Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK : GO TO NEXT STEP. 
  4. INSPECT LIGHT CONTROL RHEOSTAT 
    1. Disconnect the R6 connector.
    2. Measure the voltage between the terminal and body ground.

      Standard: 

      LIGHT CONTROL RHEOSTAT

      Tester Connection Condition Specified Condition
      R6-3 - Body ground Ignition switch is ON and lamp control switch is at TAIL or HEAD 10 to 14 V
      Fig 3: Inspecting Light Control Rheostat
      G03196867Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPLACE COMBINATION METER ASSY (See  INSTRUMENT PANEL/METER  ) 
    2. OK : GO TO NEXT STEP. 
  5. INSPECT COMBINATION METER ASSY 
    1. Check input signal waveform.
      1. Remove the combination meter but do not disconnect the connectors.
      2. Connect the oscilloscope to terminal C11-7 and body ground.
      3. Turn the ignition switch ON.
        Fig 4: Connecting Oscilloscope To Terminal C11-7 & Body Ground
        G03196868Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      4. Check the signal waveform according to COMBINATION METER ASSY  .
        COMBINATION METER ASSY

        Item Contents
        Tool setting 2V/DIV., 1 msec./DIV.
        Vehicle condition Ignition switch ON
        Fig 5: Checking Signal Waveform
        G03196869Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        OK : As shown in  Fig 5  . 

        HINT: Duty ratio changes as illumination dims ("A" becomes longer).

    1. NG : REPLACE LIGHT CONTROL RHEOSTAT 
    2. OK : REPLACE COMBINATION METER ASSY (See  INSTRUMENT PANEL/METER  ) 
  6. INSPECT LIGHT CONTROL RHEOSTAT 
    1. Measure the voltage and resistance between the terminal and body ground.

      Standard: 

      LIGHT CONTROL RHEOSTAT

      Tester Connection Condition Specified Condition
      R6-1 - Body ground Ignition switch is ON 10 to 14 V
      R6-4 - Body ground Ignition switch is ON and lamp control switch is at TAIL or HEAD 10 to 14 V
      R6-5 - Body ground Always Below 1 Ω
      Fig 6: Inspecting Light Control Rheostat
      G03196870Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK : REPLACE LIGHT CONTROL RHEOSTAT 
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