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

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON and turn the Techstream on.
(c) Select the item below in the Active Test and then check that the blower motor operates.

Active Test / Air Conditioner





Result:






C -- INSPECT BLOWER MOTOR
B -- INSPECT FUSE (HTR)
A -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. INSPECT FUSE (HTR)
(a) Remove the HTR fuse from the engine room relay block and junction block.
(b) Measure the resistance of the fuse.
Standard Resistance:






NG -- REPLACE FUSE (HTR)
OK -- Continue to next step.
3. 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:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY)




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BLOWER MOTOR)




(a) Disconnect the A/C amplifier connector.




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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. INSPECT BLOWER MOTOR
(a) Reconnect the connector to the blower motor.




(b) Measure the voltage on the A/C amplifier connector side according to the value(s) in the table below.
Standard Voltage:






NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.
7. INSPECT AIR CONDITIONING AMPLIFIER
(a) Remove the A/C amplifier.




(b) Reconnect the connector to the A/C amplifier.




(c) Turn the ignition switch to ON.
(d) Turn the blower switch on.
(e) Measure the waveform between terminal E30-23 (BLW) of the A/C amplifier and body ground.






OK:
Waveform is as shown in the illustration.
HINT: Waveform varies with the blower level.

NG -- REPLACE AIR CONDITIONING AMPLIFIER
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE