Diagnosis Procedure

BLOWER MOTOR


Description


SYSTEM DESCRIPTION

Component Parts

Fan speed control system components are:
- Front air control
- A/C LAN system (PBR built-in mode door motor, air mix door motor and intake door motor)

System Operation









BLOWER MOTOR


Diagnosis Procedure

Regarding Wiring Diagram information, refer to Coupe or Sedan.
SYMPTOM: Blower motor operation is malfunctioning.

DIAGNOSIS PROCEDURE FOR BLOWER MOTOR





SYMPTOM: Blower motor operation is malfunctioning under starting blower speed control.
1.CHECK POWER SUPPLY FOR BLOWER MOTOR





1. Turn ignition switch OFF.
2. Disconnect blower motor connector.
3. Turn ignition switch ON.
4. Check voltage between blower motor harness connector M31 terminal 4 and ground.

4 - Ground : Battery voltage

Is the inspection result normal?
YES - GO TO 2
NO - GO TO 5
2.CHECK BODY GROUND CIRCUIT FOR BLOWER MOTOR





1. Press ignition switch OFF.
2. Check continuity between blower motor harness connector M31 terminal 1 and ground.





Is the inspection result normal?
YES - GO TO 3
NO - Repair harness or connector.
3.CHECK BLOWER MOTOR CONTROL CIRCUIT BETWEEN BLOWER MOTOR AND FRONT AIR CONTROL
1. Disconnect front air control harness connector.
2. Check continuity between blower motor harness connector M31 terminal 3 and front air control harness connector M37 terminal 1.





3. Check continuity between blower motor harness connector M31 terminal 3 and ground.





Is the inspection result normal?
YES - GO TO 4
NO - Repair harness or connector.
4.CHECK FRONT AIR CONTROL OUTPUT SIGNAL





1. Reconnect blower motor connector and front air control connector.
2. Press ignition switch ON.
3. Set MODE switch to the VENT position.
4. Check the output waveform between blower motor harness connector M31 terminal 3 and ground using an oscilloscope, while varying the fan speed from 1 to 7.





Is the inspection result normal?
YES - Replace the blower motor. Refer to Blower Unit.
NO - Replace the front air control. Refer to Service and Repair.
5.CHECK FUSE
Check 15A fuses (Nos. 21 and 22).

NOTE:
Refer to Coupe (coupe) Sedan (sedan) for fuse location.
Is the inspection result normal?
YES - GO TO 6
NO - GO TO 11
6.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY
1. Press ignition switch OFF.





2. Disconnect fuse block (J/B) connector.
3. Press ignition switch ON.
4. Turn blower motor control dial to any speed except OFF.
5. Check voltage between fuse block (J/B) connector E6 terminal 6P and ground.

6P - Ground : Battery Voltage

Is the inspection result normal?
YES - GO TO 10
NO - GO TO 7
7.CHECK POWER SUPPLY FOR FRONT BLOWER MOTOR RELAY FOR AN OPEN





1. Press ignition switch OFF.
2. Disconnect BCM harness connector M19.
3. Check continuity between BCM harness connector M19 (A) terminal 90 and fuse block (J/B) harness connector E6 (B) terminal 6P.





Is the inspection result normal?
YES - GO TO 8
NO - Repair harness or connector.
8.CHECK BLOWER FAN SWITCH SIGNAL FOR VOLTAGE
1. Disconnect BCM harness connector M18.





2. Press ignition switch ON.
3. Check voltage between BCM harness connector M18 terminal
55 and ground.





Is the inspection result normal?
YES - Replace BCM. Refer to BCM.
NO - GO TO 9
9.CHECK BLOWER FAN SWITCH SIGNAL CIRCUIT FOR AN OPEN
1. Press ignition switch OFF.
2. Disconnect front air control harness connector.
3. Check continuity between BCM harness connector M18 terminal 55 and front air control harness connector M37 terminal 11.





4. Check continuity between BCM harness connector M18 terminal 55 and ground.





Is the inspection result normal?
YES - Replace front air control. Refer to Service and Repair.
NO - Repair harness or connector.
10.CHECK FRONT BLOWER MOTOR RELAY GROUND





1. Press ignition switch OFF.
2. Check continuity between fuse block (J/B) harness connector
M5 terminal 7M and ground.





Is the inspection result normal?
YES - Replace front blower motor relay.
NO - Repair harness or connector.
11.REPLACE FUSES
1. Reconnect blower motor connector.
2. Replace fuses.
3. Activate the blower motor.
Does the fuse blow?
YES - GO TO 12
NO - Inspection End.
12.CHECK BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT





1. Turn ignition switch OFF.
2. Disconnect blower motor harness connector and front air control.
3. Check continuity between blower motor harness connector M31 terminal 4 and ground.

4 - Ground : Continuity should not exist.

Is the inspection result normal?
YES - Replace blower motor. Refer to Blower Motor.
NO - Repair harness or connector.