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Home >> Lexus >> 2007 >> LS 460L >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning >> Air Conditioning System >> Blower Motor Circuit >> Inspection Procedure

Inspection Procedure

  1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER OR TECHSTREAM (BLOWER MOTOR) 
    1. Select the Active Test, using the intelligent tester or Techstream to generate a control command, and then check that the blower motor operates.
      1. Intelligent tester

        AIR CONDITIONER 

        INTELLIGENT TESTER - AIR CONDITIONER REFERENCE CHART

        Tester Display Test Part Control Range Diagnostic Note
        BLOWER MOTOR Blower motor Min.: 0, Max.: 31 -
      2. Techstream

        Air Conditioner 

        TECHSTREAM - AIR CONDITIONER REFERENCE CHART

        Tester Display Test Part Control Range Diagnostic Note
        Blower Motor Blower motor Min.: 0, Max.: 31 -

        Result 

        RESULT CHART

        Result Proceed to
        NG (blower motor does not operate) A
        NG (blower motor operates but does not change speed) B
        OK C

    B: Go to step   6 

    C: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE (See  PROBLEM SYMPTOMS TABLE   ) 

    A: GO TO NEXT STEP 

  2. INSPECT FUSE (HTR) 
    1. Remove the HTR H-fuse from the engine room No. 1 relay block.
    2. Measure the resistance of the fuse.

      Standard resistance 

      FUSE (HTR)

      Tester Connection Condition Specified Condition
      HTR H-fuse Always Below 1 Ω

    NG: REPLACE FUSE 

    OK: GO TO NEXT STEP 

  3. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND) 
    Fig 1: Checking Harness And Connector (Blower Motor - Body Ground)
    G04950463Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the A40*1 or v1*2 blower motor connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      w/o Air Suspension 

      BLOWER MOTOR - BODY GROUND (W/O AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      A40-1 (GND) - Body ground Always Below 1 Ω

      w/ Air Suspension 

      BLOWER MOTOR - BODY GROUND (W/AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      v1-1 (GND)-Body ground Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY) 
    Fig 2: Checking Harness And Connector (Blower Motor - Battery)
    G04950464Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the A40*1 or v1*2 blower motor connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      w/o Air Suspension 

      BLOWER MOTOR - BATTERY (W/O AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      A40-3 (+B) - Body ground Always 11 to 14 V

      w/ Air Suspension 

      BLOWER MOTOR - BATTERY (W/AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      v1-3 (+B) - Body ground Always 11 to 14 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  5. CHECK BLOWER MOTOR (SI VOLTAGE) 
    Fig 3: Checking Blower Motor (SI Voltage)
    G04950465Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the L76 air conditioning amplifier connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      w/o Air Suspension 

      BLOWER MOTOR (SI VOLTAGE) (W/O AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      A40-2 (SI) - Body ground Engine switch on (IG) 4.5 to 5.5 V

      w/ Air Suspension 

      BLOWER MOTOR (SI VOLTAGE) (W/O AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      v1-2 (SI) - Body ground Engine switch on (IG) 4.5 to 5.5 V

    NG: Go to step   8 

    OK: GO TO NEXT STEP 

  6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER MOTOR) 
    Fig 4: Checking Harness And Connector (Air Conditioning Amplifier - Blower Motor)
    G04950466Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the L76 air conditioning amplifier connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      AIR CONDITIONING AMPLIFIER - BLOWER MOTOR

      Tester Connection Switch Condition Specified Condition
      L76-3 (BLW) - L76-1 (GND) Engine switch on (IG) Blower switch OFF 4.5 to 5.5 V

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  7. CHECK AIR CONDITIONING AMPLIFIER (BLW SIGNAL) 
    Fig 5: Checking Air Conditioning Amplifier (BLW Signal)
    G04950467Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the air conditioning amplifier with its connectors still connected (see REMOVAL  ).
    2. Turn the engine switch on (IG).
    3. Turn the blower switch ON (Lo).
    4. Using an oscilloscope, check the waveform.

      Waveform (Reference): 

      AIR CONDITIONING AMPLIFIER (BLW SIGNAL)

      Item Contents
      Test Connector BLW{L76-3)-GND(L76-1)
      Tool Setting 1 V/DIV., 500 μUsec./DIV.
      Vehicle Condition Engine switch: on (IG)
      Blower switch: OFF → ON

      OK: Waveform is as shown in  Fig 5 . 

      HINT:

      Waveform varies with the blower level.

    NG: REPLACE AIR CONDITIONING AMPLIFIER (See  REMOVAL   ) 

    OK: REPLACE BLOWER MOTOR (See  REMOVAL   ) 

  8. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING AMPLIFIER) 
    Fig 6: Checking Harness And Connector (Blower Motor - Air Conditioning Amplifier)
    G04950468Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the L76 air conditioning amplifier connector.
    2. Disconnect the A40*1 or v1*2 blower motor connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      w/o Air Suspension 

      BLOWER MOTOR - AIR CONDITIONING AMPLIFIER (W/O AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      A40-2 (SI) - L76-3 (BLW) Always Below 1 Ω
      A40-2 (SI) - Body ground Always 10 kΩ or higher
      L76-3 (BLW) - Body ground Always 10 kΩ or higher

      w/ Air Suspension 

      BLOWER MOTOR - AIR CONDITIONING AMPLIFIER (W/AIR SUSPENSION)

      Tester Connection Condition Specified Condition
      v1-2(SI)-L76-3(BLW) Always Below 1 Ω
      v1-2 (SI) - Body ground Always 10 kΩ or higher
      L76-3 (BLW) - Body ground Always 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE BLOWER MOTOR (See  REMOVAL   ) 

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