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. The blower motor speed is controlled using various duty ratios.

Duty Ratio:

* The duty ratio is the ratio of the blower motor ON time (A) 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

HINT
* AUTO A/C: Start inspection from step 1.
* MANUAL A/C: Start inspection from step 2.

PROCEDURE

1. PERFORM ACTIVE TEST 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 Active Test and then check that the blower motor operates.

Active Test / Air Conditioner:

Result:

C -- INSPECT BLOWER MOTOR

B -- INSPECT FUSIBLE LINK (HTR)

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

2. INSPECT FUSIBLE LINK (HTR)

(a) Remove the fusible link from the engine room R/B.

(b) Check if the fusible link is melted.

OK:

The point indicated by "A" is not melted.

(c) Install the fusible link to the engine room R/B with the nut.

NG -- REPLACE FUSIBLE LINK (HTR)
OK -- Continue to next step.

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

(a) Disconnect the blower motor connector.

(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.

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

(a) Disconnect the blower motor connector.

(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.

5. CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - BLOWER MOTOR)

(a) Disconnect the A/C amplifier connector.

(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.

6. INSPECT BLOWER MOTOR

(a) Reconnect the connector to the blower motor.

(b) Measure the voltage on the A/C amplifier connector side according to the value(s) in the table below.

Standard voltage:

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

7. INSPECT AIR CONDITIONING AMPLIFIER

(a) Remove the A/C amplifier.

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

(d) Turn the blower switch ON.

(e) Measure the waveform between terminal E38-23 (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 -- REPLACE AIR CONDITIONING AMPLIFIER

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