Heater blower motors control the fan that offers airflow into the passenger area of the vehicle as well as running the heating and air conditioning systems of the vehicle.

How Do You Know You Have a Problem with your Heater Blower Motor?

The first symptom is a fan that makes strange noises such as squeaks or clanking which then may stop and the fan speed may then alter.

The second most common symptom is that you can hear the fan working, but there is no air coming through the vent.

The third symptom is that the fan only works on one speed which is high.  This is a clear indication that the blower motor resistor has broken and needs replacing.