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 battery negative (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. 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.

Possible causes of an inoperative blower motor include:

- Open fuse
- Inoperative blower motor power module or resistor (depending on system)
- Inoperative blower motor
- Inoperative blower motor switch
- Inoperative A/C heater module
- Blower motor circuit wiring or wire harness connectors

Possible causes of the blower motor not operating in all speeds include:

- Inoperative blower motor power module or resistor (depending on system)
- Inoperative blower motor switch
- Inoperative A/C heater module
- Inoperative blower motor circuit wiring or wire harness connectors

VIBRATION

Possible causes of blower motor vibration include:

- Improper blower motor mounting
- Blower wheel out of balance or deformed
- Foreign material in blower wheel causing out of balance condition
- Worn 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 and A/C system. If the noise goes away, possible causes include:

- Improper blower motor mounting
- Foreign material in blower wheel
- Foreign material in housing
- Worn blower motor