Blower Motor Circuit

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

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

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body / Air Conditioner / Active Test.
(e) Check the operation by referring to the table below.

Air Conditioner





OK:
Blower motor operates and blower motor speed level changes.
Result:





C -- INSPECT A/C AMPLIFIER
B -- CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND)
A -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE
2. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND)




(a) Disconnect the blower motor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

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




(a) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - A/C AMPLIFIER)




(a) Disconnect the A/C amplifier connector.




(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. INSPECT BLOWER MOTOR
(a) Reconnect the blower motor connector.




(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:





Text in Illustration





NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.

6. INSPECT A/C AMPLIFIER




(a) Remove the A/C amplifier.
(b) Reconnect the A/C amplifier connector.
(c) Turn the ignition switch to ON.
(d) Turn the blower switch LO.
(e) Measure the waveform between terminal D47-23 (BLW) of the A/C amplifier and body ground.





OK:
Waveform is as shown in the illustration.
HINT: The waveform varies with the blower speed.

Text in Illustration





NG -- REPLACE A/C AMPLIFIER
OK -- REPLACE BLOWER MOTOR