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

DESCRIPTION

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

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

   1. Connect the Techstream to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the Techstream on.

   4. Enter the following menus: Body Electrical / 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 with fan motor sub-assembly	Min.: 0, Max.: 31	-

      Result
      Result Proceed to OK A NG (Blower with fan motor sub-assembly does not operate) B NG (Blower with fan motor sub-assembly operates but does not change speed) C

   B

   CHECK HARNESS AND CONNECTOR (BLOWER WITH FAN MOTOR SUB-ASSEMBLY - BODY GROUND) Click here

   C

   INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

   A

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

2. CHECK HARNESS AND CONNECTOR (BLOWER WITH FAN MOTOR SUB-ASSEMBLY - BODY GROUND)

   1. Disconnect the I76 blower with fan motor sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition I76-1 (GND) - Body ground Always Below 1 Ω

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

3. CHECK HARNESS AND CONNECTOR (BLOWER WITH FAN MOTOR SUB-ASSEMBLY - BATTERY)

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

      Standard Voltage
      Tester Connection Condition Specified Condition I76-3 (+B) - Body ground Always 11 to 14 V

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BLOWER WITH FAN MOTOR SUB-ASSEMBLY)

   1. Disconnect the I77 air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition I77-22 (BLW) - I76-2 (SI) Always Below 1 Ω I77-22 (BLW) - Body ground Always 10 kΩ or higher

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. INSPECT BLOWER WITH FAN MOTOR SUB-ASSEMBLY

   1. Reconnect the I76 blower with fan motor sub-assembly connector.

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

      

      Standard Voltage
      Tester Connection Condition Specified Condition I77-22 (BLW) - Body ground Always 4.5 to 5.5 V

      Text in Illustration

      *a	Front view of wire harness connector (to Air Conditioning Amplifier Assembly)

   NG

   REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY Click here

   OK

6. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

   1. Remove the air conditioning amplifier assembly Click here.

      

   2. Reconnect the air conditioning amplifier assembly connector.

   3. Turn the ignition switch to ON.

   4. Turn the blower switch on (LO).

   5. Measure the waveform between terminal I77-22 (BLW) of the air conditioning amplifier assembly and body ground.

      OK
      Waveform is similar to that shown in the illustration.

      Tech Tips

      The waveform varies with the blower speed.

      Item	Content
      Tool setting	1 V/DIV., 500 μs/DIV.
      Vehicle condition	Ignition switch ON Blower switch on (LO)

      Text in Illustration

      *a	Component with harness connected (Air Conditioning Amplifier Assembly)

   NG

   REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

   OK

   REPLACE BLOWER WITH FAN MOTOR SUB-ASSEMBLY Click here