Blower Motor: Testing and Inspection

WARNING: On vehicles equipped with air bags, refer to Air Bags And Seat Belts/air Bags before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Failure to take the proper precautions could result in accidental air bag deployment and possible personal injury.

POSSIBLE CAUSES
Possible causes of an inoperative blower motor include:
- Faulty fuse
- Faulty blower motor relay
- Faulty blower motor battery feed circuit
- Faulty blower motor ground circuit
- Faulty blower motor circuit wiring or wire harness connectors
- Faulty blower motor resistor
- Faulty blower motor switch
- Faulty heater-A/C mode control switch
- Faulty blower motor.

Possible causes of the blower motor not operating in all speeds include:
- Faulty fuse
- Faulty blower motor relay
- Faulty blower motor battery feed circuit
- Faulty blower motor resistor
- Faulty blower motor circuit wiring or wire harness connectors.
- Faulty blower motor switch.

Vibration
Possible causes of blower motor vibration include:
- Improper blower motor mounting
- Improper blower wheel mounting
- Blower wheel out of balance or bent
- Blower motor faulty

Noise
To verify that the blower is the source of the noise, unplug the blower motor wire harness connector and operate the heater-A/C system. If the noise goes away possible causes include:
- Foreign material in the heater-A/C housing
- Improper blower motor mounting
- Improper blower wheel mounting
- Blower motor faulty