How To Replace Your Central A/C System's Blower Fan Motor

Your HVAC system relies on its blower fan to circulate conditioned air throughout your home. When it stops, so does the flow of cool, comfortable air. The blower fan motor is usually the culprit and, in most cases, it needs to be replaced. The following offers a brief guide on how you can save a few bucks by replacing your central A/C system's blower fan motor on your own.

First Steps

Your very first step should be to locate the blower fan motor. On most units, it's normally located behind the HVAC system's protective outside cover. The motor itself will look like a small barrel that's laying on its side with several wires coming from its housing.

Before you do anything else, you'll want to disconnect power to the HVAC system, since the blower fan motor is usually hardwired into your home's main electrical supply. Locate the circuit breaker for the HVAC system and switch it off. Afterwards, use a noncontact circuit tester on the motor's wiring to make sure the circuit is not live.

Out With the Old...

Make a note of the motor wire colors and their connections before you begin removing the motor. It's a good idea to not only take pictures, but also write down the wire colors and where they go. Afterwards, you can proceed to disconnect the wiring.

There should be a couple of fasteners located at the front of the blower fan assembly. Use a socket wrench to remove these bolts and slide the blower fan assembly out of the HVAC system. Afterwards, locate the set screw holding the wheel on the blower motor to the outside assembly. Loosen the set screw and remove the mounting screws holding the motor in place. Then you can remove the set screw and finally disconnect the motor.

...And in With the New

Make sure the new motor you're installing is compatible with the specifications listed for the blower assembly. In other words, the new motor should have the same horsepower, motor diameter and rotation direction as well as voltage and speed of the old motor.

The installation process is the reverse of the removal. Use the documentation you created for wiring to connect the motor to the HVAC system correctly. After the motor has been properly connected to the HVAC system, you can turn on the circuit breaker and test the unit to make sure everything works correctly after the ac repair.