AIR CONDITIONING SYSTEM Blower Motor Circuit

DESCRIPTION

A001D4KE06

The blower motor is operated by signals from the air conditioning amplifier. Blower motor speed signals are transmitted by changes in the duty ratio.

Duty Ratio:

The duty ratio is the ratio of the blower motor ON time (A) to the total of the blower motor ON and OFF time (A + B).

The blower motor controller controls the blower motor speed.

WIRING DIAGRAM

A001ADDE10

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (BLOWER MOTOR)


    1. Select the Active Test, using the intelligent tester to generate a control command, and then check that the blower motor operates.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Blower Motor Blower motor Min.: 0, Max.: 31 -
      Result
      Result Proceed to
      NG (blower motor does not operate) A
      NG (blower motor operates but does not change speed) B
      OK C

    B

    CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER MOTOR) Click here

    C

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    A

  2. INSPECT FUSE (HTR)


    1. Remove the HTR H-fuse from the No. 1 engine room relay block.

    2. Measure the resistance of the fuse.

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

    NG

    REPLACE FUSE

    OK

  3. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND)

    A001D8BE01

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

  4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY)

    A001926E03

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

  5. CHECK BLOWER MOTOR (SI VOLTAGE)

    A001ELDE02

    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
      Tester Connection Switch Condition Specified Condition
      A40-2 (S1) - Body ground Engine switch on (IG) 4.5 to 5.5 V
      w/ Air Suspension
      Tester Connection Switch Condition Specified Condition
      v1-2 (S1) - Body ground Engine switch on (IG) 4.5 to 5.5 V

    NG

    CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING AMPLIFIER) Click here

    OK

  6. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - BLOWER MOTOR)

    A001DHXE03

    1. Disconnect the L76 air conditioning amplifier connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      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

  7. CHECK AIR CONDITIONING AMPLIFIER (BLW SIGNAL)


    1. Remove the air conditioning amplifier with its connectors still connected Click here.

      A00191ZE01
      *a Component with harness connected: (Air Conditioning Amplifier)
      *b 1 V/DIV.
      *c 500 μsec./DIV.

    2. Turn the engine switch on (IG).

    3. Turn the blower switch ON (Lo).

    4. Using an oscilloscope, check the waveform.

      Waveform (Reference):
      Item Contents
      Test Connector BLW (L76-3) - GND (L76-1)
      Tool Setting 1 V/DIV., 500 μsec./DIV.
      Vehicle Condition

      Engine switch: on (IG)

      Blower switch: OFF → ON
      OK
      Waveform is as shown in the illustration.

      Tech Tips

      Waveform varies with the blower level.


    OK

    REPLACE BLOWER MOTOR Click here

    NG

    REPLACE AIR CONDITIONING AMPLIFIER Click here

  8. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING AMPLIFIER)

    A001D3GE01

    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
      Tester Connection Condition Specified Condition
      A40-2 (S1) - L76-3 (BLW) Always Below 1 Ω
      A40-2 (S1) - Body ground Always 10 kΩ or higher
      L76-3 (BLW) - Body ground Always 10 kΩ or higher
      w/ Air Suspension
      Tester Connection Condition Specified Condition
      v1-2 (S1) - L76-3 (BLW) Always Below 1 Ω
      v1-2 (S1) - Body ground Always 10 kΩ or higher
      L76-3 (BLW) - Body ground Always 10 kΩ or higher

    OK

    REPLACE BLOWER MOTOR Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR