What is a Blower Motor, and How Can You Test One?

A hand holding a car air conditioner blower motor against a white background. — Without a blower motor, your car's A/C is useless. imran kadir photography / Getty Images

A blower motor is an electric motor that powers a fan or blower, creating a flow of air or gas. The primary function of blower motors is to ensure that air circulates efficiently in desired environments. This circulation can involve either bringing fresh air into a space or expelling stale or heated air out.

In this article, we'll take a closer look at what blower motors accomplish across a range of applications. We'll also help you troubleshoot a failing blower motor in your car, which could otherwise impact your heating and cooling system.

A Crucial Component in Your HVAC System

In HVAC systems, blower motors are indispensable. They are responsible for moving hot or cold air through the ducts of your air conditioning or heating systems, ensuring even distribution of air within a building.

In heating systems, the blower motor pushes heat generated by the furnace through the ductwork. Conversely, in air conditioning systems, it circulates cooled air. The effectiveness of an HVAC system is heavily reliant on the efficiency and reliability of its blower motor.

Automotive Applications

In automobiles, HVAC blower motors are a key component of heating systems and air conditioners. They are responsible for circulating heated or cooled air throughout the vehicle's cabin, maintaining a comfortable temperature regardless of exterior weather conditions. A bad blower motor in a vehicle can lead to a lack of airflow from the car's vents, directly impacting passenger comfort.

Industrial and Commercial Uses

Beyond HVAC and automotive applications, furnace blower motors are used in a variety of industrial and commercial settings. For instance, they are essential in air filtration systems, removing pollutants and maintaining air quality in industrial environments.

For example, in settings such as cleanrooms and laboratory environments, this HVAC equipment works in conjunction with filtration and climate control systems to maintain strict air quality and temperature standards. This precise control is crucial in industries like pharmaceuticals, biotechnology, and electronics manufacturing, where even minor fluctuations in environmental conditions can impact the quality and safety of products.

They also play a crucial role as a cooling system for electronic components and machinery, preventing overheating and potential damage. Think of them as a mini HVAC unit within lots of modern technology.

Enhanced Integration with Smart Home Systems

In the realm of modern furnaces, blower motors have evolved to seamlessly integrate with smart home technologies, elevating their functionality and user convenience. An advanced furnace blower motor can be connected to a smart thermostat and home automation system, allowing for precise control over heating patterns and energy usage.

This integration enables homeowners to adjust furnace blower settings remotely via smartphone apps, ensuring optimal comfort and efficiency. Furthermore, smart systems can provide real-time diagnostics and performance data, alerting users if they need to have their furnace checked.

This proactive approach to maintenance can prevent costly repairs and prolong the lifespan of the furnace. A smart furnace blower motor is a major evolution of home heating solutions.

How to Test an HVAC Blower Motor

Your car's HVAC blower motor is not only necessary for the operation of your air conditioner. Without a functioning blower motor your engine runs the risk of overheating. If you hear that the system's fan is operating but don't feel any air flowing through the vents, the problem is with the airflow controls [source: RepairPal]. If the blower motor isn't running you should:

Use voltmeter or ohmmeter to check for a blown fuse. If you find one, replace it.
Start car and see if the blower motor works. If fuse blows again, check for loose circuits.
If the circuits are in good repair but the blower motor keeps blowing fuses, replace the blower motor [source: You Fix Cars].

If your engine's working fine but the HVAC blower motor is suffering from variable speed or unusual noises, you can test it to see if it needs cleaning or repair. Here's what to do:

Disconnect car battery.
Detach the blower motor from its connector.
Unscrew all the screws on the blower motor. Place them in small container.
Locate the retainer clip in the center of the blower wheel. Disconnect it from the motor shaft and set aside.
Clean out any debris from the motor.
Clean the blower motor with an electrical-parts cleaner.
Oil the bearings.
Check that the blower wheel spins freely and all the other parts are operating properly. If a part isn't working properly, clean and oil it, and test it again [sources: PartSource].

If you can get the HVAC blower motor working again, reinstall it. If not, you'll have to buy a new blower motor.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.