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Headlight Dimmer Switch Circuit [08/2020 - ]: Procedure

  1. READ VALUE USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Combination Meter / Data List.
    5. Read the Data List according to the display on the Techstream.
      MAIN BODY

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Dimmer SW Headlight dimmer switch High position signal/
      ON or OFF      		 OFF: Headlight dimmer switch not in High position
      ON: Headlight dimmer switch in High position      		 -
      Passing Light SW Headlight dimmer switch Flash position signal/
      ON or OFF      		 OFF: Headlight dimmer switch not in Flash position
      ON: Headlight dimmer switch in Flash position      		 -
      Front Fog Light SW Fog light switch Fr position signal/
      ON or OFF      		 OFF: Fog light switch off
      ON: Fog light switch in Fr position      		 w/ Front Fog Light
      Auto Light SW Light control switch AUTO position signal/
      ON or OFF      		 OFF: Light control switch not in AUTO position
      ON: Light control switch in AUTO position      		 -
      Head Light SW (Head) Light control switch HEAD position signal/
      ON or OFF      		 OFF: Light control switch not in HEAD position
      ON: Light control switch in HEAD position      		 -
      Head Light SW (Tail) Light control switch TAIL position signal/
      ON or OFF      		 OFF: Light control switch not in TAIL position
      ON: Light control switch in TAIL position      		 -

      OK

      Normal conditions listed above are displayed.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ] 

    Result: 

    NG 

    See step  2

  2. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY (LIGHT CONTROL SWITCH, DIMMER SWITCH) 
    1. Remove the headlight dimmer switch assembly.

      Refer to REMOVAL [08/2015 - ]

    2. Inspect the headlight dimmer switch assembly.

      Refer to INSPECTION [08/2020 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to  REMOVAL [08/2015 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] AND BODY GROUND) 
    1. Disconnect the G31 headlight dimmer switch assembly connector.
    2. Disconnect the G130 main body ECU (multiplex network body ECU) connectors.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G130-22 (TAIL) - G31-18 (T) Always Below 1 Ω
      G130-12 (HEAD) - G31-19 (H) Always Below 1 Ω
      G130-8 (A) - G31-20 (A) Always Below 1 Ω
      G130-24 (HU) - G31-14 (HU) Always Below 1 Ω
      G130-10 (HF) - G31-17 (HF) Always Below 1 Ω
      G130-26 (FFOG) - G31-9 (BFG)* Always Below 1 Ω
      G31-8 (LFG) - Body ground Always Below 1 Ω
      G31-15 (EL) - Body ground Always Below 1 Ω
      G130-22 (TAIL) - Body ground Always 10 kΩ or higher
      G130-12 (HEAD) - Body ground Always 10 kΩ or higher
      G130-8 (A) - Body ground Always 10 kΩ or higher
      G130-24 (HU) - Body ground Always 10 kΩ or higher
      G130-10 (HF) - Body ground Always 10 kΩ or higher
      G130-26 (FFOG) - Body ground* Always 10 kΩ or higher
      1. *: w/ Front Fog Light

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2019 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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