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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting System (W/O AFS) - Symptom Tests & Circuit Tests (2 Of 2) >> LIGHTING SYSTEM (w/o AFS) >> High Beam Headlight Circuit [11/2023 - ] >> Procedure

High Beam Headlight Circuit [11/2023 - ]: Procedure

  1. PERFORM ACTIVE TEST USING GTS 
    1. Perform the Active Test according to the display on the GTS.

      Body Electrical > Main Body > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      High Beam Headlight High beam headlights OFF or ON -

      Body Electrical > Main Body > Active Test 

      Tester Display
      High Beam Headlight

      OK

      High beam headlights illuminate.

      Result

      Result Proceed to
      OK A
      NG (w/ Projector Headlight (for LED Type Parking Light)) B
      NG (w/ Projector Headlight (for Bulb Type Parking Light), w/o Projector Headlight) C

    Result: 

    A 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2023 - ] 

    Result: 

    C 

    See step  6

    Result: 

    B 

    See step  2

  2. INSPECT DIMMER RELAY 

    Refer to ON-VEHICLE INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE DIMMER RELAY 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE - DIMMER RELAY) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2 (DIMMER relay) - Body ground Ignition switch off 11 to 14 V
      5 (DIMMER relay) - Body ground Ignition switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (DIMMER RELAY - HEADLIGHT ASSEMBLY) 
    1. Disconnect the A66 headlight assembly LH connector.
    2. Disconnect the A65 headlight assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (DIMMER relay) - A66-6 (HI) Always Below 1 Ω
      3 (DIMMER relay) - A65-6 (HI) Always Below 1 Ω
      3 (DIMMER relay) or A66-6 (HI) - Body ground Always 10 kΩ or higher
      3 (DIMMER relay) or A65-6 (HI) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (DIMMER RELAY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. Disconnect the H135 main body ECU (multiplex network body ECU) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (DIMMER relay) - H135-22 (DIM) Always Below 1 Ω
      1 (DIMMER relay) or H135-22 (DIM) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (HEADLIGHT ASSEMBLY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)) 
    1. Disconnect the A66 headlight assembly LH connector.
    2. Disconnect the A65 headlight assembly RH connector.
    3. Disconnect the H135 main body ECU (multiplex network body ECU) connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A66-2 (HI) - H135-22 (DIM) Always Below 1 Ω
      A65-2 (HI) - H135-22 (DIM) Always Below 1 Ω
      A66-2 (HI) or H135-22 (DIM) - Body ground Always 10 kΩ or higher
      A65-2 (HI) or H135-22 (DIM) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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