Rear Blower Motor Circuit

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: Rear Blower Motor Circuit
- Rear Blower Motor Circuit

DESCRIPTION

The rear blower with fan motor sub-assembly is operated by signals from the air conditioning amplifier. Rear blower motor speed signals are transmitted in accordance with changes in the duty ratio.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (REAR BLOWER WITH FAN MOTOR)

(a) Select the Active Test, use the Techstream to generate a control command, and then check that the rear blower with fan motor sub-assembly operates Scan Tool Testing and Procedures.

Air Conditioner

OK:

Rear blower with fan motor sub-assembly operates and rear blower with fan motor sub-assembly speed changes.

NG -- CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROL - BATTERY AND BODY GROUND)

OK -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

2. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROL - BATTERY AND BODY GROUND)

(a) Disconnect the Q12 control connector.

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

Standard Voltage:

Text in Illustration

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

3. INSPECT REAR BLOWER WITH FAN MOTOR SUB-ASSEMBLY

(a) Remove the rear blower with fan motor sub-assembly Removal.

(b) Apply battery voltage to the rear blower with fan motor sub-assembly and check the operation of the rear blower with fan motor sub-assembly.

OK:

NG -- REPLACE REAR BLOWER WITH FAN MOTOR SUB-ASSEMBLY Removal
OK -- Continue to next step.

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

(a) Disconnect the G12 amplifier connector.

(b) Disconnect the Q12 control connector.

(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.

5. CHECK HARNESS AND CONNECTOR (BLOWER MOTOR CONTROL - REAR BLOWER WITH FAN MOTOR)

(a) Disconnect the Q12 control connector.

(b) Disconnect the Q14 motor connector.

(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 (REAR BLOWER WITH FAN MOTOR - BODY GROUND)

(a) Disconnect the Q14 motor connector.

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

Standard Resistance:

Text in Illustration

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

7. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the air conditioning amplifier assembly with its connectors still connected Removal.

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

Standard Voltage:

Text in Illustration

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

8. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the air conditioning amplifier assembly with its connectors still connected Removal.

(b) Using an oscilloscope, check the waveform.

OK:

Waveform is as shown in the illustration.

Text in Illustration

HINT
Waveform varies with the blower level.

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

9. REPLACE BLOWER MOTOR CONTROL

(a) Replace the blower motor control with a new or normally functioning one Disassembly.

(b) Operate the rear blower with fan motor sub-assembly to check that it functions properly.

OK:

Rear blower with fan motor sub-assembly operates normally.

NG -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal

OK -- END (BLOWER MOTOR CONTROL IS FAULTY)