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 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

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Select the item below in the Active Test and then check that the motor operates.

Active Test / Air Conditioner





Result





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

B -- CHECK WIRE HARNESS (A/C AMPLIFIER - BLOWER MOTOR AND BODY GROUND)
A -- Continue to next step.

2. INSPECT FUSE (HEATER)

(a) Remove the HEATER and DC/DC H-fuses from the engine room No. 1 junction block.

(b) Measure the resistance of the H-fuses.

Standard resistance:

Below 1 Ohms

NG -- REPLACE FUSE
OK -- Continue to next step.

3. CHECK WIRE HARNESS (BLOWER MOTOR - BODY GROUND)





(a) Disconnect the k1 blower motor connector.

(b) Measure the resistance of the wire harness side connector.

Standard resistance:





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

4. CHECK WIRE HARNESS (BLOWER MOTOR - BATTERY)





(a) Disconnect the k1 blower motor connector.

(b) Measure the voltage of the wire harness side connector.

Standard voltage:





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

5. CHECK BLOWER MOTOR





(a) Disconnect the K52 A/C amplifier connector.

(b) Measure the voltage of the connector.

Standard voltage:





NG -- CHECK WIRE HARNESS (BLOWER MOTOR - A/C AMPLIFIER)
OK -- Continue to next step.

6. CHECK WIRE HARNESS (A/C AMPLIFIER - BLOWER MOTOR AND BODY GROUND)





(a) Disconnect the K52 A/C amplifier connector.

(b) Measure the voltage of the wire harness side connector.

Standard voltage:





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

7. CHECK AIR CONDITIONING AMPLIFIER (BLW SIGNAL)

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





(b) Turn the power switch ON (IG).

(c) Turn the blower switch ON (Lo).

(d) Using an oscilloscope, check the waveform 1.

Waveform 1 (Reference):





OK:

Waveform is as shown in the illustration.

HINT
Waveform varies with the blower level.

NG -- REPLACE AIR CONDITIONING AMPLIFIER

OK -- REPLACE BLOWER MOTOR

8. CHECK WIRE HARNESS (BLOWER MOTOR - A/C AMPLIFIER)





(a) Disconnect the K52 A/C amplifier connector.

(b) Disconnect the k1 blower motor connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE BLOWER MOTOR