Virtually all road going vehicles are equipped with a heating and air conditioning system that is designed to help keep the vehicle’s passengers comfortable. One of the components of that system is the heater blower motor. The blower motor serves as the main electric motor that is responsible for blowing air through the vents. It is usually controlled by the blower motor resistor and switch, and can operate at several different speeds to help regulate cabin temperatures.
When the heater blower motor fails, the vehicle can be left without a properly functioning heating and air conditioning system, which apart from compromising comfort, can also disable useful functions such as the window defogger. Usually a bad or failing heater blower motor will produce a few symptoms that can alert the driver of a potential issue.
1. Weak airflow from the vents
One of the first symptoms of a potential problem with the vehicle’s heater blower motor is low airflow from the vents. If when the air or heat is turned on the vents blower noticeably less, or weaker air, that may be a sign that the heater blower motor is starting to wear out. A worn or weakened blower motor may not be able to provide adequate airflow to properly regulate the cabin temperature, and may also be approaching the end of its service life.
2. Fan only blows at certain speeds
Another symptom of a bad or failing heater blower motor is a motor that only functions at certain speeds. Most blower motors are designed to operate at different speeds in order to be able to regulate different cabin temperatures efficiently. If the blower motor fails to push air at any of it’s designed settings then it may be faulty. This can also be caused by a failed blower motor resistor or switch, so having the vehicle properly diagnosed is highly recommended.
3. No air from the vents
No air flow from the vents when the heater or air conditioning is activated is another symptom of a bad blower motor. If the heater blower motor burns out or short circuits, it will not function, and therefore will not be able to produce any airflow for the system. The blower motor will usually have to be replaced in order to restore proper operation to the system.
A faulty blower motor can disable an otherwise fully functional heating and air conditioning system, which will make the driving experience less comfortable for the vehicle’s passengers. Failed blower motors often require taking apart the vehicle’s interior, so if you suspect that your vehicle’s blower motor may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the motor should be replaced.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Heater Blower Motor and was authored by Eduardo Ruelas.