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 A/C amplifier assembly. Blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, A is the period of continuity in one cycle, and B is the period of non-continuity.
The blower motor controller controls the blower motor speed.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTUATOR CHECK
(a) Set the actuator check mode (Actuator Check).
(b) Press the blower switch to change to the step operation.
(c) Check the air flow level by hand.





OK:
Blower level changes in accordance with each display code.
NG -- CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER - A/C AMPLIFIER)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER - A/C AMPLIFIER)





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





(a) 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. INSPECT BLOWER W/FAN MOTOR SUB-ASSEMBLY





(a) Remove the blower w/ fan motor sub-assembly.
(b) Connect positive (+) lead to terminal B3-2 of the blower motor connector and negative (-) lead to terminal B3-1.
Standard:
Blower motor operates smoothly.
NG -- REPLACE BLOWER W/FAN MOTOR SUB-ASSEMBLY
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER - BLOWER MOTOR)





(a) 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 AIR CONDITIONING AMPLIFIER (BLW - BODY GROUND)





(a) Remove the A/C amplifier with the connectors still connected.
(b) Turn the ignition switch to the ON position.
(c) Turn the blower switch on (Lo).
(d) Measure the waveform between terminal A32-12 (BLW) of the A/C amplifier and body ground.
OK:
Waveform operate as shown in the illustration.





HINT: Waveform varies with the blower level.

NG -- REPLACE AIR CONDITIONING AMPLIFIER
OK -- REPLACE BLOWER MOTOR CONTROL