Blower Motor: Testing and Inspection

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE THE NEGATIVE BATTERY (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY OR DEATH.

NOTE: For circuit descriptions and diagrams, refer to Air Conditioning/Heater in Wiring Diagrams.

OPERATION
Possible causes of an inoperative blower motor include:
- Faulty fuse
- Faulty blower motor resistor or power module (depending on application)
- Faulty blower motor switch
- Faulty mode control switch
- Faulty blower motor
- Faulty blower motor circuit wiring or wire harness connectors

Possible causes of the blower motor not operating in all speeds include:
- Faulty fuse
- Faulty blower motor resistor or power module (depending on application)
- Faulty blower motor switch
- Faulty blower motor
- Faulty blower motor circuit wiring or wire harness connectors

VIBRATION
POSSIBLE CAUSES of blower motor vibration include:
- Improper blower motor mounting
- Improper blower wheel mounting
- Deformed blower wheel
- Out of balance blower wheel due to foreign material in the wheel
- Faulty blower motor

NOISE
To determine if the blower motor is the source of the noise, simply switch the blower motor from Off to On. To verify that the blower motor is the source of the noise, unplug the blower motor wire harness connector and operate the heating-A/C system. If the noise goes away, possible causes include:
- Foreign material in the HVAC air inlet housing
- Improper blower motor mounting
- Improper blower wheel mounting
- Faulty blower motor