Blower Motor Circuit

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

Blower Motor Circuit

DESCRIPTION

The blower motor is operated by signals from the air conditioning amplifier. Blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio:





The duty ratio is the ratio of the blower motor OFF time (B) to the total of the blower motor ON and OFF time (A + B).
The blower motor controller controls the blower motor speed.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (BLOWER MOTOR)
(a) Select the Active Test, using the Techstream to generate a control command, and then check that the blower motor operates.

Air Conditioner





Result





C -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
B -- CHECK BLOWER MOTOR (S1 VOLTAGE)
A -- Continue to next step.
2. INSPECT FUSE (HTR)
(a) Remove the HTR H-fuse from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





NG -- REPLACE FUSE
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY AND BODY GROUND)





(a) Disconnect the J32 blower motor connector.
(b) Measure the resistance and voltage according to the value(s) in the table below.
Standard resistance:





Standard voltage:





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





(a) Disconnect the J19 air conditioning amplifier connector.
(b) Disconnect the J32 blower motor connector.
(c) 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.
5. CHECK BLOWER MOTOR (S1 VOLTAGE)





(a) Disconnect the J19 air conditioning amplifier connector.
(b) Reconnect the J32 blower motor connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.
6. CHECK AIR CONDITIONING AMPLIFIER (BLW VOLTAGE)





(a) Remove the air conditioning amplifier with its connectors still connected (Removal).
(b) Turn the ignition switch ON.
(c) Turn the blower switch LO.
(d) Using an oscilloscope, check the waveform.
Standard:





HINT: Waveform varies with the blower level.

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