How to Replace a Furnace Fan

man woriking on a furnace
  • 5-10 hours
  • Advanced
  • 500-2,000
What You'll Need
Replacement furnace fan and motor
Adjustable wrench
Tarp or old blanket
New furnace filter

Often called a blower, the furnace fan is usually one of the most reliable parts of any furnace. However, if its motor burns out, or it stops functioning for some other reason, it is fairly simple to replace the furnace fan and motor yourself. Save money and time by following these guidelines to replace your furnace fan.

Step 1 - Determine the Exact Model of Furnace Fan You Need

If your furnace is still under warranty, get the exact serial number and model of the furnace, and contact the manufacturer or the dealer you bought it from to get a new fan, motor, and filters. If your furnace's warranty has ended, consider buying a reconditioned furnace fan. It will have a limited warranty, but will function well at a substantially lower cost than new. Contact the company that usually services your furnace to find a supplier of reconditioned parts.

Step 2 - Locate the Furnace Fan and Motor Assembly

inside of a furnace

Turn off the furnace and disconnect it from any electrical sources. Lay your tarp or old blanket beside the furnace. Find the access panel for the furnace fan, covered by an access panel on the side of your furnace. Release the clips on the access panel and remove it from the furnace.

Step 3 - Remove the Fan and Motor Assembly

The fan and motor assembly are mounted on a tray that slides out. Pull the sliding tray out toward you by the handle under the motor. The motor assembly will be attached to the tray by three bolts. Use a suitable type of screwdriver or an adjustable wrench to remove the motor assembly. Check how the wires are connected so you can reattach them on the correct spots on the new motor. There will usually be white and black wires, and red, yellow, and blue if the furnace also provides air conditioning. Set the old fan and motor on the tarp or blanket.

Step 4 - Clean and Replace the Furnace Filter

holding a furnace filter

A clean furnace filter will help your fan and motor run more efficiently and reduce wear on the new fan. Remove the old filter and put in a new one.

Step 5 - Replace the Motor Assembly and Fan

Detach the motor assembly from the fan by releasing the bolts. Check the furnace fan for cleanliness, proper lubrication, corrosion, or bent fan blades. If the fan is in excellent condition, reinstall it with the replacement motor. If the fan is damaged, do not reuse it - install the entire replacement fan and motor assembly. Put the new motor assembly and fan on the sliding tray and reconnect the wires to their appropriate locations. Slide the tray into the furnace and affix the access panel again.

Step 6 - Test the Furnace Fan and Motor Assembly

Restore electrical power to the furnace, and turn it on to test the function of the new fan and motor assembly. Listen for rattles, squeaks, or other noises that indicate loose bolts, parts, or lack of lubrication.