Blower Motor Circuit

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 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.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch ON and turn the intelligent tester main switch on.
(c) Select the item below in the DATA LIST, and read the display on the intelligent tester.

DATA LIST / AIR CONDITIONER:





OK:
The display is as specified in the normal condition.
NG -- PERFORM ACTIVE TEST USING INTELLIGENT TESTER
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. PERFORM ACTIVE TEST USING INTELLIGENT TESTER
(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch ON and turn the intelligent tester main switch on.
(c) Select the item below in the ACTIVE TEST and then check that the blower motor operates.

ACTIVE TEST / AIR CONDITIONER:





OK:
Blower motor operates and blower level changes.
NG -- PERFORM ACTUATOR CHECK
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3. PERFORM ACTUATOR CHECK
(a) Set the actuator check mode Actuator Check.
(b) Press the blower switch to change to the step operation.
(c) Check for 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
4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER - A/C AMPLIFIER)





(a) Disconnect the connector from the A/C amplifier and blower motor controller.
(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.
5. 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.
6. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER, BLOWER MOTOR - BATTERY)





(a) Disconnect the connector from the blower motor.
(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.
7. 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.
8. INSPECT BLOWER MOTOR





(a) Remove the blower motor.
(b) Connect the negative (-) lead to terminal 1 of blower motor connector, and the positive (+) lead to terminal 2.
OK:
Blower motor operates smoothly.
NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.
9. INSPECT AIR CONDITIONING AMPLIFIER





(a) Reconnect the connector to the A/C amplifier.
(b) Turn the ignition switch ON.
(c) Blower speed control switch is at "LO" position.





(d) Measure the waveform between terminal BLW (A8-9) of the A/C amplifier assembly and body ground.
OK:
Waveform appears as shown in the illustration.
HINT: Waveform cycle varies with the blower level.

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