AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) Blower Motor Circuit

DESCRIPTION

A0156D2E01

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

Duty Ratio:

The duty ratio is the ratio of the blower motor OPEN time (T1) to the total of the blower motor OPEN and LO time (T2).

The blower motor controller controls the blower motor speed.

WIRING DIAGRAM

A015AMHE03
A015AMHE04

INSPECTION PROCEDURE

PROCEDURE


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


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

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

    B

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

    C

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

    A

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

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

    A015AIYE19

    1. Disconnect the A29 motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A29-1 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    A015AIYE20

    1. Disconnect the A29 motor connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A29-3 (+B) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK FRONT BLOWER MOTOR (SI VOLTAGE)

    A0157G6E18

    1. Disconnect the E36*1 or E81*2 amplifier connector.

    2. Reconnect the A29 motor connector.

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

      Tech Tips

      *1: for LHD

      *2: for RHD

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A29-2 (SI) - Body ground Engine switch on (IG) 4.5 to 5.5 V

    NG

    REPLACE FRONT BLOWER MOTOR Click here

    OK

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


    1. A0155VCE06

      w/ Rear Heater


      1. Disconnect the E36 amplifier connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        E36-3 (BLW) - E36-1 (GND)

        Engine switch on (IG)

        Blower switch off

        		 4.5 to 5.5 V
    2. A0156WWE01

      w/o Rear Heater


      1. Disconnect the E81 amplifier connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        E81-23 (BLW) - E81-1 (GND)

        Engine switch on (IG)

        Blower switch off

        		 4.5 to 5.5 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

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


    1. A0155VCE06

      w/ Rear Heater


      1. Disconnect the E36 amplifier connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        E36-3 (BLW) - E36-1 (GND)

        Engine switch on (IG)

        Blower switch off

        		 4.5 to 5.5 V
    2. A0156WWE01

      w/o Rear Heater


      1. Disconnect the E81 amplifier connector.

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

        Standard Voltage
        Tester Connection Switch Condition Specified Condition
        E81-23 (BLW) - E81-1 (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 ASSEMBLY (BLW SIGNAL)


    1. A015BRXE03

      w/ Rear Heater


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

      2. Using an oscilloscope, check the waveform.

        Measurement Condition
        Item Content
        Terminal No. (Symbol) E36-3 (BLW) - E36-1 (GND)
        Tool Setting 1 V/DIV., 500 μsec./DIV.
        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.

    2. A015D4DE01

      w/o Rear Heater


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

      2. Using an oscilloscope, check the waveform.

        Measurement Condition
        Item Content
        Terminal No. (Symbol) E81-23 (BLW) - E81-1 (GND)
        Tool Setting 1 V/DIV., 500 μsec./DIV.
        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.


    NG

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    OK

    REPLACE FRONT BLOWER MOTOR Click here