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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/ Manual A/C) - Diagnostic Codes, Circuit Tests & Symptom Tests >> AIR CONDITIONING SYSTEM (for Gasoline Model with Manual Air Conditioning System) >> Rear Blower Motor Circuit [12/2019 - 10/2022] >> Procedure

Rear Blower Motor Circuit [12/2019 - 10/2022]: Procedure

  1. PERFORM ACTIVE TEST USING GTS (REAR 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
      Rear Blower Motor Rear blower motor with fan sub-assembly Min.: 0
      Max.: 31      		 -

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Rear Blower Motor

      Result

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

    Result: 

    B 

    See step  6

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR CONTROL - POWER SOURCE AND BODY GROUND) 
    1. Disconnect the M14 rear blower motor control connector.
      GTY929826Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Rear Blower Motor Control)
    2. Measure the voltage and resistance according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      M14-1 (+B) - Body ground Ignition switch off 11 to 14 V

      Standard Resistance

      Tester Connection Condition Specified Condition
      M14-6 (GND) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. INSPECT REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY 

    Refer to INSPECTION [12/2019 - ]

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

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

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR WITH FAN SUB-ASSEMBLY - REAR BLOWER MOTOR CONTROL AND BODY GROUND) 
    1. Disconnect the M14 rear blower motor control connector.
    2. Disconnect the M13 rear 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
      M13-2 (+) - M14-2 (VM) Always Below 1 Ω
      M13-1 (-) - Body ground Always Below 1 Ω
      M13-2 (+) or M14-2 (VM) - 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  5

  5. CHECK HARNESS AND CONNECTOR (REAR BLOWER MOTOR CONTROL - AIR CONDITIONING AMPLIFIER ASSEMBLY) 
    1. Disconnect the M14 rear blower motor control connector.
    2. Disconnect the H64 air conditioning amplifier assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M14-3 (SI) - H64-10 (SBLW) Always Below 1 Ω
      M14-3 (SI) or H64-10 (SBLW) - 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  6

  6. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Connect the M14 rear blower motor control connector.
    2. Connect the M13 rear blower motor with fan sub-assembly connector.
    3. Connect the H64 air conditioning amplifier assembly connector.
    4. Using an oscilloscope, check the waveform.
      GTY864239Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Air Conditioning Amplifier Assembly)      		 - -
      Item Content
      Terminal No. H64-10 (SBLW) - H64-4 (GND2)
      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 REAR BLOWER MOTOR CONTROL. Refer to  REMOVAL [12/2019 - 11/2023] 

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [12/2019 - 10/2022] 

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