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

DESCRIPTION

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

The rear blower motor controller controls the rear blower with fan motor sub-assembly speed.

WIRING DIAGRAM

B001ZA6E03

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS (REAR BLOWER MOTOR)


    1. Select the Active Test, use the GTS to generate a control command, and then check that the rear blower with fan motor sub-assembly operates Click here.

      Air Conditioner
      Tester Display Test Part Control Range Diagnostic Note
      Rear Blower Motor Rear blower with fan motor sub-assembly Min.: 0, Max.: 31 -
      OK
      Rear blower with fan motor sub-assembly is operated normally using the GTS.

    OK

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

    NG

  2. INSPECT REAR BLOWER WITH FAN MOTOR SUB-ASSEMBLY


    1. Remove the rear blower with fan motor sub-assembly Click here.

    2. Inspect the rear blower with fan motor sub-assembly Click here.


    NG

    REPLACE REAR BLOWER WITH FAN MOTOR SUB-ASSEMBLY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY - BATTERY AND BODY GROUND)


    1. B001WZV
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Wiring Air Conditioning Harness Sub-assembly)

      Disconnect the wiring air conditioning harness sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      4 - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the wiring air conditioning harness sub-assembly connector.

    2. Disconnect the E36 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      8 - E36-17 (BLWH) Always Below 1 Ω
      8 or E36-17 (BLWH) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY


    1. Replace the wiring air conditioning harness sub-assembly with a new or known good one and check that the condition returns to normal.

      OK
      Same problem does not occur.

    OK

    END (WIRING AIR CONDITIONING HARNESS SUB-ASSEMBLY WAS DEFECTIVE)

    NG

  6. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY


    1. B001YR5E02

      Using an oscilloscope, check the waveform.

      Measurement Condition
      Item Content
      Terminal No. (Symbol) z51-3 (SI) - Body ground
      Tool Setting 2 V/DIV., 500 μs/DIV.
      Condition

      • Ignition switch ON

      • Blower switch LO
      OK
      Waveform is as shown in the illustration.

      Tech Tips

      Waveform varies with the blower level.


    OK

    REPLACE BLOWER MOTOR CONTROL Click here

    NG

  7. CHECK BLOWER MOTOR CONTROL


    1. Replace the blower motor control with a new or known good one and check that the condition returns to normal.

      OK
      Same problem does not occur.

    OK

    END (BLOWER MOTOR CONTROL WAS DEFECTIVE)

    NG

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here