Diagnosis Procedure

BLOWER MOTOR


Diagnosis Procedure

1.PERFORM SELF-DIAGNOSIS STEP-4
Perform self-diagnosis STEP-4. Refer to Diagnosis Description, see Nos. 1 to 5.





Does blower motor speed change according to each code No.?
YES - INSPECTION END
NO - GO TO 2.
2.CHECK POWER SUPPLY FOR BLOWER MOTOR
1. Disconnect blower motor connector.
2. Turn ignition switch ON.
3. Check voltage between blower motor harness connector and ground.





Is the inspection result normal?
YES - GO TO 3.
NO - GO TO 6.
3.CHECK BLOWER MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between blower motor harness connector and ground.





Is the inspection result normal?
YES - GO TO 4.
NO - Repair harness or connector.
4.CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.
2. Check continuity between blower motor harness connector and unified meter and A/C amp. harness connector.





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





Is the inspection result normal?
YES - GO TO 5.
NO - Repair harness or connector.
5.CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL
1. Reconnect blower motor connector and unified meter and A/C amp. connector.
2. Turn ignition switch ON.
3. Set MODE switch to VENT position.
4. Change fan speed from Lo to Hi, and check duty ratios between blower motor harness connector and ground by using an oscilloscope.

NOTE:
Calculate the drive signal duty ratio as shown in the figure.





T2 = 1.6 ms










Is the inspection result normal?
YES - Replace blower motor after confirming the fan air flow does not change.
NO - Replace unified meter and A/C amp.
6.CHECK POWER VOLTAGE OF BLOWER RELAY
1. Turn ignition switch OFF.
2. Remove blower relay.
3. Turn ignition switch ON.
4. Check the voltage between blower relay fuse block terminals and ground.


Is the inspection result normal?
YES - GO TO 7.
NO - Check ignition power supply circuit.
7.CHECK BLOWER RELAY
1. Turn ignition switch OFF.
2. Install blower relay.00
3. Check operation sound of the blower relay after switching ignition switch ON.
Is the inspection result normal?
YES - GO TO 8.
NO - Replace blower relay.
8.CHECK FUSE
Check fuse 15A [Nos 21 and 22, located in the fuse block (J/B).
Is the inspection result normal?
YES - Repair harness or connector.
NO - Be sure to eliminate cause of malfunction before installing new fuse.