AIR CONDITIONING SYSTEM Blower Motor Circuit

DESCRIPTION

The blower motor is operated by signals from the A/C amplifier. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.

WIRING DIAGRAM

A01NDHRE05

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Air Conditioner / Active Test.

    5. Check the operation by referring to the table below.

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

    B

    CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND) Click here

    C

    INSPECT A/C AMPLIFIER Click here

    A

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

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


    1. A01NHUXE18
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Blower Motor)

      Disconnect the blower motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F47-1 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. A01NHUXE19
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Blower Motor)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      F47-3 (+B) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - A/C AMPLIFIER)


    1. A01NDH4E43

      Disconnect the A/C amplifier connector.

    2. A01NHUXE20
      Text in Illustration
      *1

      Front view of wire harness connector

      (to A/C Amplifier)
      *2

      Front view of wire harness connector

      (to Blower Motor)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F50-23 (BLW) - F47-2 (SI) Always Below 1 Ω
      F50-23 (BLW) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT BLOWER MOTOR


    1. Reconnect the blower motor connector.

    2. A01NDH4E44
      Text in Illustration
      *1

      Front view of wire harness connector

      (to A/C Amplifier)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      F50-23 (BLW) - Body ground Always 4.5 to 5.5 V

    NG

    REPLACE BLOWER MOTOR Click here

    OK

  6. INSPECT A/C AMPLIFIER


    1. A01NCQ9E17
      Text in Illustration
      *1

      Component with harness connected

      (A/C Amplifier)

      Remove the A/C amplifier.

    2. Reconnect the A/C amplifier connector.

    3. Turn the power switch on (IG).

    4. Set the blower speed to low.

    5. Measure the waveform between terminal F50-23 (BLW) of the A/C amplifier and body ground.

      Item Content
      Tool setting 1 V/DIV., 500 μs/DIV.
      Vehicle condition

      Power switch on (IG)

      Blower set to low
      OK
      Waveform is as shown in the illustration.

      Tech Tips

      The waveform varies with the blower speed.


    NG

    REPLACE A/C AMPLIFIER Click here

    OK

    REPLACE BLOWER MOTOR Click here