AIR CONDITIONING SYSTEM Rear Blower Motor Circuit

DESCRIPTION

A001D4KE05

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

Duty Ratio:

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

The rear blower motor controller controls the rear blower motor speed.

WIRING DIAGRAM

A001BQYE05
w/ Rear Cooler Unit
*a from Battery
*b RR A/C
*c Rear Blower Motor
*d Air Conditioning Amplifier

PROCEDURE


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


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

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

    B

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

    C

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

    A

  2. INSPECT FUSE (RR A/C)


    1. Remove the RR A/C H-fuse from the engine room No. 1 relay block.

    2. Measure the resistance of the fuse.

      Standard resistance
      Tester Connection Condition Specified Condition
      RR A/C H-fuse Always Below 1 Ω

    NG

    REPLACE FUSE

    OK

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

    A001EDRE02
    *1 Front view of wire harness connector: (to Rear Blower Motor)

    1. Disconnect the v3 rear blower motor connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      v3-1 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    A001C6BE02
    *1 Front view of wire harness connector: (to Rear Blower Motor)

    1. Disconnect the v3 rear blower motor connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      v3-3 (+B) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK REAR BLOWER MOTOR (SI VOLTAGE)

    A001FP1E02
    *1 Component with harness connected: (Rear Blower Motor)

    1. Disconnect the v3 rear blower motor connector.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      v3-2 (SI) - Body ground Engine switch on (IG) 4.5 to 5.5 V

    NG

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

    OK

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

    A001DRCE03

    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
      L76-17 (SBLW) - 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 (SBLW SIGNAL)


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

      A001AROE02
      *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 rear blower switch ON (Lo).

    4. Using an oscilloscope, check the waveform.

      Waveform (Reference):
      Item Contents
      Test Connector SBLW (L76-17) - 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 REAR BLOWER MOTOR Click here

    NG

    REPLACE AIR CONDITIONING AMPLIFIER Click here

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

    A001D91E04
    *1 Front view of wire harness connector: (to Rear Blower Motor)
    *2 Rear view of wire harness connector: (to Air Conditioning Amplifier)

    1. Disconnect the L76 air conditioning amplifier connector.

    2. Disconnect the v3 rear blower motor connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      v3-2 (SI) - L76-17 (SBLW) Always Below 1 Ω
      v3-2 (SI) - Body ground Always 10 kΩ or higher
      L76-17 (SBLW) - Body ground Always 10 kΩ or higher

    OK

    REPLACE REAR BLOWER MOTOR Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR