Blower Motor: Testing and Inspection

DIAGNOSIS AND TESTING - BLOWER MOTOR

WARNING: 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 may result in accidental airbag deployment and possible serious or fatal injury.

NOTE: See Wiring Information for circuit descriptions and diagrams.

OPERATION

Possible causes of an inoperative blower motor include:

- Open fuse
- Inoperative A/C heater module
- Inoperative blower motor
- Inoperative blower motor power module
- Inoperative blower motor relay
- Inoperative blower motor switch
- Inoperative blower motor wiring or wire harness connectors

NOISE

To determine if the blower motor is the source of the noise, simply switch the blower motor on and off. To verify that the blower motor is the source of the noise, unplug the blower motor wire harness connector and operate the heating and A/C system. If the noise goes away, possible causes include:

- Deformed or damaged blower wheel
- Foreign material in blower wheel
- Foreign material in the HVAC housing
- Foreign material on fresh air inlet screen
- Improper blower motor mounting
- Worn blower motor bearings or brushes

VIBRATION

Possible causes of blower motor vibration include:

- Deformed or damaged blower wheel
- Foreign material in blower wheel
- Improper blower motor mounting
- Worn blower motor bearings