Blower Motor Circuit

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 by changes in the Duty Ratio.

Duty Ratio
- The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then Duty Ratio = A/(A+B) x 100 (%).





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position and turn Techstream on.
(c) Select the item below in the Data List, and read the display on Techstream.

Data List / Air Conditioner:





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

Active Test / Air Conditioner:





OK:
The blower motor operates and the blower level changes.
NG -- PERFORM ACTUATOR CHECK
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
3. PERFORM ACTUATOR CHECK
(a) Enter the actuator check mode Check Mode Procedure.
(b) Press the DEF switch to change to the step operation.
(c) Check the air flow level by hand.






OK:
The blower level changes in accordance with each display code.
NG -- INSPECT BLOWER MOTOR
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
4. INSPECT BLOWER MOTOR





(a) Remove the blower motor.
(b) Disconnect the connector from the blower motor.
(c) Connect the positive (+) lead from the battery to terminal 2 and the negative (-) lead to terminal 1, and check that the motor operates.
OK:
Blower motor operates smoothly.
NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BLOWER MOTOR CONTROLLER)
(a) Disconnect the connector from the blower motor.





(b) Disconnect the connector from the blower motor controller.
(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.
6. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - 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.
7. 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.
8. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROLLER - BATTERY)





(a) 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.
9. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BLOWER MOTOR CONTROLLER)





(a) Disconnect the connector from the A/C amplifier.
(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.
10. INSPECT A/C AMPLIFIER





(a) Reconnect the connector to the A/C amplifier.
(b) Reconnect the connector to the blower motor controller.
(c) Reconnect the connector to the blower motor.





(d) Measure the waveform between terminal A9-6 (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 -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE BLOWER MOTOR CONTROLLER