AIR CONDITIONING SYSTEM Blower Motor Circuit

DESCRIPTION

The blower motor is operated by signals from the A/C amplifier. Blower motor speed signals are transmitted in accordance with changes in the duty ratio.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the engine switch on (IG).

   3. Turn the intelligent tester on.

   4. Select the item below in the Active Test and then check that the relay operates.

      Active Test / Air Conditioner

      Tester Display	Test Part	Control Range	Diagnostic Note
      Blower Motor (Blower Motor)	Blower motor	Min.: 0, Max.: 31	-

      Result
      Result Proceed to OK A NG (blower motor does not operate) B NG (blower motor operates but does not change speed) C

   
   

   B

   INSPECT FUSE (HEATER) Click here

   C

   CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND) Click here

   A

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

2. INSPECT FUSE (HEATER)

   
   

   1. 

      Remove the HEATER fuse from the engine room relay block and junction block No. 1.

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

      Standard Resistance
      Tester Item Condition Specified Condition HEATER fuse Always Below 1 Ω

   
   

   NG

   REPLACE FUSE (HEATER)

   OK

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

   
   

   1. 

      Disconnect the blower motor connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition b1-1 (GND) - Body ground Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

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

   
   

   1. 

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

      Standard Voltage
      Tester Connection Condition Specified Condition b1-3 (+B) - Body ground Always 11 to 14 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. INSPECT BLOWER MOTOR

   
   

   1. 

      Reconnect the blower motor connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition b1-2 (S1) - Body ground Always 4.5 to 5.5 V

   
   

   NG

   REPLACE BLOWER MOTOR Click here

   OK

6. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BODY GROUND)

   
   

   1. 

      Disconnect the A/C amplifier connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition J58-11 (BLW) - Body ground Always 4.5 to 5.5 V

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. INSPECT AIR CONDITIONING AMPLIFIER

   
   

   1. 

      Remove the A/C amplifier.

   2. Reconnect the A/C amplifier connector.

   3. Turn the engine switch on (IG) .

   4. Turn the blower switch on (LO).

   5. Measure the waveform between terminal J58-11 (BLW) of the A/C amplifier and body ground.

      OK
      Waveform is as 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	Engine switch on (IG) Blower switch ON (LO)

   
   

   NG

   REPLACE A/C AMPLIFIER Click here

   OK

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