AIR CONDITIONING SYSTEM Rear Blower Motor Circuit

DESCRIPTION

A000V3HE05

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

A000VJEE07

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
      Rear blower motor operates normally A
      Rear blower motor does not operate B
      Rear blower motor operates but does not change speed C

    A

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

    C

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

    B

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

      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 AIR CONDITIONING HARNESS - BODY GROUND)

    A000WLYE01
    *1 Front view of wire harness connector: (to Rear Air Conditioning Harness)

    1. Disconnect the S90 rear air conditioning harness connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      S90-5 (GND) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (REAR AIR CONDITIONING HARNESS - BATTERY)

    A000TRNE01
    *1 Front view of wire harness connector: (to Rear Air Conditioning Harness)

    1. Disconnect the S90 rear air conditioning harness connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      S90-9 (+B) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK REAR AIR CONDITIONING HARNESS (SI VOLTAGE)

    A000U5ZE01
    *1 Component with harness connected: (Rear Air Conditioning Harness)

    1. Disconnect the L76 air conditioning amplifier connector.

    2. Reconnect the S90 rear air conditioning harness connector.

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

      Standard voltage
      Tester Connection Switch Condition Specified Condition
      S90-13 (SI) - Body ground Power switch ON (IG) 4.5 to 5.5 V

    NG

    REPLACE REAR AIR CONDITIONING HARNESS Click here

    OK

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

    A000YJBE01
    *1 Rear view of wire harness connector: (to Air Conditioning Amplifier)

    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 Condition Specified Condition
      L76-17 (SBLW) - L76-1 (GND)

      Power 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.

      A001000E02
      *a Component with harness connected: (Air Conditioning Amplifier)
      *b 1 V/DIV.
      *c 500 μsec./DIV.

    2. Using an oscilloscope, check the waveform.

      Measurement condition
      Item Content
      Tester Connection L76-17 (SBLW) - L76-1 (GND)
      Tool Setting 1 V/DIV., 500 μsec./DIV.
      Condition

      Power 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 Click here

    OK

  8. REPLACE REAR AIR CONDITIONING HARNESS


    1. Replace the rear air conditioning harness with a normal one and check that the condition returns to normal Click here.

      OK
      Same problem does not occur.

    OK

    END (REAR AIR CONDITIONING HARNESS IS DEFECTIVE)

    NG

    REPLACE REAR BLOWER MOTOR Click here