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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Accessories & Equipment >> Heated Glass/Defoggers >> Windshield Deicer System - Diagnostics & Symptom Tests >> Windshield Deicer System >> Windshield Deicer does not Operate [12/2019 - 10/2022] >> Procedure

Windshield Deicer does not Operate [12/2019 - 10/2022]: Procedure

  1. SYSTEM CHECK 
    1. Check the vehicle specification.

      Result

      Result Proceed to
      For 8 Inch Display A
      For 12.3 Inch Display B

    Result: 

    B 

    See step  5

    Result: 

    A 

    See step  2

  2. CHECK AIR CONDITIONING SYSTEM 
    1. Check that the air conditioning system.

      HINT: 

      Both the windshield deicer system operation signal and air conditioning system operation signal are transmitted to the air conditioning amplifier assembly through the same communication line.

      OK

      The air conditioning system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO AIR CONDITIONING SYSTEM 

    For HV Model: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2021] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2021 - 11/2023]

    For Gasoline Model with Automatic Air Conditioning System: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022]

    For Gasoline Model with Manual Air Conditioning System: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022]

    Result: 

    OK 

    See step  3

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

      Body Electrical > Air Conditioner > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Deicer Relay (Front) Windshield deicer wire (windshield glass) OFF or ON -

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Deicer Relay (Front)

      OK

      The windshield deicer system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  4

  4. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Replace the air conditioning amplifier assembly with a new or known good one.

      Refer to REMOVAL [12/2019 - 10/2022]

    2. Check that the windshield deicer system operates normally.

      OK

      The windshield deicer system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (AIR CONDITIONING AMPLIFIER ASSEMBLY WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE AIR CONDITIONING CONTROL ASSEMBLY 

  5. CHECK HARNESS AND CONNECTOR (FRONT WIPER DEICER SWITCH - POWER SUPPLY) 
    1. Disconnect the H37 front wiper deicer switch connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H37-5 (IG) - Body ground Ignition switch ON 11 to 14 V
      H37-5 (IG) - Body ground Ignition switch off Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (FRONT WIPER DEICER SWITCH - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H37-2 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (FRONT WIPER DEICER SWITCH - DEICER RELAY) 
    1. Remove the DEICER relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      DEICER relay holder terminal 1 - H37-4 (D) Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. INSPECT FRONT WIPER DEICER SWITCH 

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

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPLACE FRONT WIPER DEICER SWITCH. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    OK 

    See step  9

  9. INSPECT DEICER RELAY 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω
      3 - 5 Auxiliary battery voltage not applied between terminals 10 kΩ or higher
      GTY329933Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE DEICER RELAY 

    Result: 

    OK 

    See step  10

  10. CHECK WIRE HARNESS AND CONNECTOR (DEICER RELAY - POWER SUPPLY) 
    1. Measure the voltage according to the value(s) in the table below.
      GTY863372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a DEICER Relay Holder

      Standard Voltage

      Tester Connection Condition Specified Condition
      DEICER relay holder terminal 2 - Body ground Ignition switch ON 11 to 14 V
      DEICER relay holder terminal 3 - Body ground Ignition switch off*1
      Always*2      		 11 to 14 V
      1. *1: for HV Model
      2. *2: for Gasoline Model

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  11

  11. CHECK WIRE HARNESS AND CONNECTOR (DEICER RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY) 
    1. Disconnect the H62 air conditioning amplifier assembly connector.
      GTY863372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a DEICER Relay Holder
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      DEICER relay holder terminal 1 - H62-22 (FDEF) Always Below 1 Ω
      DEICER relay holder terminal 1 or H62-22 (FDEF) - Body ground Always 10 kΩ higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  12

  12. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Connect the H62 air conditioning amplifier assembly connector.
    2. Measure the voltage according to the value(s) in the table below.
      GTY861685Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Air Conditioning Amplifier Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      H62-22 (FDEF) - H62-17 (GND) Ignition switch ON, Front wiper deicer switch on Below 1 V
      H62-22 (FDEF) - H62-17 (GND) Ignition switch ON, Front wiper deicer switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 

    Result: 

    OK 

    See step  13

  13. CHECK WIRE HARNESS AND CONNECTOR (DEICER RELAY - WINDSHIELD DEICER WIRE (WINDSHIELD GLASS)) 
    1. Disconnect A60 windshield deicer wire (windshield glass) connector.
      GTY863372Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a DEICER Relay Holder
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      DEICER relay holder terminal 5 - A60-1 (B) Always Below 1 Ω
      DEICER relay holder terminal 5 - A60-3 (B2) Always Below 1 Ω
      A60-1 (B) - Body ground Always 10 kΩ higher
      A60-3 (B2) - Body ground Always 10 kΩ higher
      DEICER relay holder terminal 5 - Body ground Always 10 kΩ higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  14

  14. CHECK WIRE HARNESS AND CONNECTOR (WINDSHIELD DEICER WIRE (WINDSHIELD GLASS) - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A60-2 (E) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE WINDSHIELD DEICER WIRE (WINDSHIELD GLASS). Refer to  REMOVAL [12/2019 - 09/2020]  , or refer to  REMOVAL [09/2020 - 10/2021]  , or refer to  REMOVAL [10/2021 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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