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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Heating / Air Conditioning System (Except HV, W/ Auto A/C) - Circuit Tests & Symptom Tests >> AIR CONDITIONING SYSTEM (for Gasoline Model with Automatic Air Conditioning System) >> Blower Motor Circuit [11/2023 - ] >> Procedure

Blower Motor Circuit [11/2023 - ]: Procedure

  1. PERFORM ACTIVE TEST USING GTS (BLOWER MOTOR) 
    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
      Blower Level This test activates the blower motor to adjust the air volume high/low.
      (Blower motor with fan sub-assembly)      		 0: Air Volume Low
      31: Air Volume High      		 Operate with the ignition switch ON.

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Blower Level

      Result

      Result Proceed to
      Blower motor with fan sub-assembly does not operate A
      Blower motor with fan sub-assembly operates but does not change speed B

    Result: 

    B 

    See step  5

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR WITH FAN SUB-ASSEMBLY - BATTERY AND BODY GROUND) 
    1. Disconnect the H134 blower motor with fan sub-assembly connector.
      GTY1178930Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Rear view of wire harness connector
      (to Blower Motor with Fan Sub-assembly)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H134-1 (GND) - Body ground Always Below 1 Ω
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H134-3 (+B) - 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  3

  3. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BLOWER MOTOR WITH FAN SUB-ASSEMBLY) 
    1. Disconnect the H62 air conditioning amplifier assembly connector.
    2. Disconnect the H134 blower motor with fan sub-assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      H62-21 (BLW) - H134-2 (SI) Always Below 1 Ω
      H62-21 (BLW) or H134-2 (SI) - Other terminals and body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK BLOWER MOTOR WITH FAN SUB-ASSEMBLY 
    1. Connect the H134 blower motor with fan sub-assembly connector.
    2. Disconnect the H62 air conditioning amplifier assembly connector.
      GTY907690Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Air Conditioning Amplifier Assembly)
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      H62-21 (BLW) - Body ground Always 4.75 to 5.25 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY. Refer to  REMOVAL [12/2019 - ] 

    Result: 

    OK 

    See step  5

  5. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Connect the H62 air conditioning amplifier assembly connector.
    2. Using an oscilloscope, check the waveform.
      GTY914298Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Air Conditioning Amplifier Assembly)      		 - -
      Item Content
      Terminal No. H62-21 (BLW) - H62-17 (GND)
      Tool Setting 2 V/DIV., 1 ms./DIV.
      Condition
      • Ignition switch ON
      • Blower speed: LO

      OK

      Waveform is similar to that shown in the illustration.

      HINT: 

      The waveform varies with the blower speed.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLOWER MOTOR WITH FAN SUB-ASSEMBLY. Refer to  DISASSEMBLY [12/2019 - ] 

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [11/2023 - ] 

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