Blower Motor Circuit

AIR CONDITIONING: 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, B is the period of non-continuity.

The blower motor controller controls the blower motor speed.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch on (IG) 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.

NG -- REPLACE AIR CONDITIONING AMPLIFIER
OK -- Continue to next step.

2. CHECK ACTUATOR

(a) Set the actuator check mode Actuator Check.

(b) Press the UPDr switch to set the step operation.

(c) Check the air flow level by hand.





OK:

Blower level changes in accordance with each display code.

NG -- INSPECT FUSE (HEATER)

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

3. INSPECT FUSE (HEATER)

(a) Remove the HEATER fuse from the engine room R/B and J/B.





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

Standard Resistance:





NG -- REPLACE FUSE (HEATER)
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the connector from blower motor.





(b) Disconnect the connector from the A/C amplifier.





(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

5. 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 AND CONNECTOR
OK -- Continue to next step.

6. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY)

(a) Measure the voltage according to the value(s) in the table below.





Standard Voltage:





NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

7. INSPECT BLOWER MOTOR

(a) Remove the blower motor.





(b) Connect positive (+) lead to terminal 3 of the blower motor connector and negative (-) lead to terminal 1.

OK:

Blower motor operates smoothly.

NOTICE:
While using the battery during inspection, do not bring the positive and negative tester probes too close to each other as a short circuit may occur.

NG -- REPLACE BLOWER MOTOR
OK -- Continue to next step.

8. INSPECT AIR CONDITIONING AMPLIFIER (BLW - BODY GROUND)

(a) Reconnect the connector to the blower motor.





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

(c) Remove the A/C amplifier with connectors still connected.

(d) Turn the ignition switch on (IG).

(e) Press the blower switch on (LO).

(f) Measure the waveform between terminal BLW (D37-11) of the A/C amplifier and body ground.





HINT
Waveform varies with the blower level.

NG -- REPLACE AIR CONDITIONING AMPLIFIER

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE