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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) >> Front Fog Light Circuit [11/2023 - ] >> Procedure

Front Fog Light Circuit [11/2023 - ]: Procedure

  1. READ VALUE USING GTS 
    1. Read the Data List according to the display on the GTS.

      Body Electrical > Power Distribution Box > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Front Fog Light External Relay Input Signal Front fog light external relay input OFF or ON OFF: Front fog light is not input
      ON: Front fog light is input      		 -

      Body Electrical > Power Distribution Box > Data List 

      Tester Display
      Front Fog Light External Relay Input Signal

      OK

      Display changes according to the front fog light switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  2

  2. READ VALUE USING GTS 
    1. Using the GTS, read the Data List.

      Body Electrical > Power Distribution Box > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Front Fog Light External Relay Output Signal Front fog light external relay output OFF or ON OFF: Front fog lights off
      ON: Front fog lights on      		 -

      Body Electrical > Power Distribution Box > Data List 

      Tester Display
      Front Fog Light External Relay Output Signal

      OK

      Display changes according to the front fog light switch operation.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (POWER DISTRIBUTION BOX ASSEMBLY - BODY GROUND) 
    1. Disconnect the 8B and 8C power distribution box assembly connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      8B-44 - Body ground Always Below 1 Ω
      8C-25 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. INSPECT FOG FR RELAY 

    HINT: 

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

    Result

    Result Proceed to
    OK (except Sport Package) A
    OK (for Sport Package) B
    NG C

    Result: 

    B 

    See step  7

    Result: 

    C 

    REPLACE FOG FR RELAY 

    Result: 

    A 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the A59 fog light assembly LH connector.
    2. Disconnect the A58 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - A59-2 (B) Always Below 1 Ω
      3 (FOG FR relay) - A58-2 (B) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (FOG LIGHT ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A59-1 (E) - Body ground Always Below 1 Ω
      A58-1 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the B8 fog light assembly LH connector.
    2. Disconnect the B7 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - B8-2 (B) Always Below 1 Ω
      3 (FOG FR relay) - B7-2 (B) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (FOG LIGHT ASSEMBLY - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B8-1 (E) - Body ground Always Below 1 Ω
      B7-1 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  9. CHECK HARNESS AND CONNECTOR (POWER SOURCE - FOG FR RELAY) 
    1. Remove the FOG FR relay.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2 (FOG FR relay) - Body ground Always 11 to 14 V
      5 (FOG FR relay) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. INSPECT FOG FR RELAY 

    HINT: 

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

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE FOG FR RELAY 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - POWER DISTRIBUTION BOX ASSEMBLY) 
    1. Disconnect the 8G power distribution box assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      1 (FOG FR relay) - 8G-28 Always Below 1 Ω

      Result

      Result Proceed to
      OK (except Sport Package) A
      OK (for Sport Package) B
      NG C

    Result: 

    B 

    See step  13

    Result: 

    C 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the A59 fog light assembly LH connector.
    2. Disconnect the A58 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - Body ground Always 10 kΩ or higher
      A59-2 (B) - Body ground Always 10 kΩ or higher
      A58-2 (B) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  13. CHECK HARNESS AND CONNECTOR (FOG FR RELAY - FOG LIGHT ASSEMBLY) 
    1. Disconnect the B8 fog light assembly LH connector.
    2. Disconnect the B7 fog light assembly RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 (FOG FR relay) - Body ground Always 10 kΩ or higher
      B8-2 (B) - Body ground Always 10 kΩ or higher
      B7-2 (B) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE POWER DISTRIBUTION BOX ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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