How To Replace a Furnace Blower Motor and Capacitor

By | June 21, 2023

How To Replace a Furnace Blower Motor and Capacitor 44
A furnace blower motor can be replaced by a handy DIY homeowner, which can save money.

Of course, if in-doubt, be sure to call a professional HVAC technician.

A new motor and capacitor will need to be bought to replace the old unit.

Most hardware stores will not carry a furnace motor, but a new unit can be bought easily online on Amazon or eBay.

Read Here For How To Buy a New Furnace Blower Motor and Capacitor

How To Replace a Furnace Blower Motor and Capacitor

  1. Turn the power off to the furnace.
  2. Be sure to turn off the power to the furnace or unplug it before any work is done to a motor or any components.

  3. Locate the furnace blower motor.
  4. The first step is to locate the motor, which is the only large motor in the furnace.

    Here is a furnace motor assembly and capacitor bolted onto the assembly.
    How To Replace a Furnace Blower Motor and Capacitor Step 2

  5. Locate the Furnace Capacitor.
  6. Look for a Start or RUN Capacitor since this will also have to be changed (if the furnace has one). A bad or failing capacitor can damage a new motor, so it must be changed any time a new motor is installed.

    Some furnaces don’t have a RUN or Start capacitor, which can vary between units.

  7. Take pictures of the blower motor and capacitor.
  8. Before anything is removed or any work done, take pictures and write down all the wiring and connections.

    Take good pictures or a video to refer back to later if needed. If something is wired wrong, the motor may burn up, or at the very least, not work. Having pictures to look back at can be invaluable when reconnecting everything.

    Once you have good pictures of the wiring, the wires can be unplugged and removed.

  9. Remove the blower motor assembly.
  10. The motor will be inside of a sheet metal assembly, making it necessary to remove the entire assembly.
    How To Replace a Furnace Blower Motor and Capacitor
    Screws holding it in are usually located in the front with a notch in the back it can slide out of.

  11. Remove the fan blades.
  12. Once the entire assembly is taken out the bolts holding the fan blades in place need to be removed.
    Replaceing a Furnace Blower Motor and Capacitor
    One bolt will hold onto the shaft and needs to be loosened to slide off.

    To remove it, loosen it up so that the shaft can pull out from the fan blades. It is a good idea to oil up the end of the shaft so it pulls out easier as some can be a pain. If there is any rust or build-up on the shaft, use sandpaper to remove it and then oil it. Otherwise, pulling a motor from the fan blades can be very hard sometimes.

  13. Remove blower motor bracket.
  14. Next, the bolts holding the back of the blower motor should be removed, and the motor pulled from the fan blades.
    How To Replace a Furnace Blower Motor
    On a side note, it is a good idea to clean the fan blades when the assembly is out. Debris build-up on fan blades makes them work less efficiently; cleaning them is always a good idea. If the fan blades are very dirty, take them to a car wash and, after spraying them with de-greaser, power wash them.

    The motor will have a ring that goes around it and bolts to the housing; this should be taken off the old motor and put on the new one. In some cases, it can be damaged if it has been a new one can be bought.
    Furnace Blower Motor Bolts
    Once the ring has been placed on the new motor, the shaft can be slid back onto the fan blades and bolted into place.

  15. Bolt the fan blades back into place.
  16. When bolting the fan blades in, they will need to be centered, so the blades spin freely in the housing. Furnace blower motor spin freeley

    Before tightening the bolt on the shaft, be sure it is centered correctly since there is a flat spot on the shaft that is where the bolt screws into holding it in place.
    Furnace Blower Motor Shaft

    Before installing the assembly back into the furnace, be sure the fan blades spin without hitting the housing.

    Remember to connect the ground wire to the case.
    Furnace blower Motor Ground Wire

  17. Install the new capacitor.
  18. Install the new capacitor and connect the correct wires from the motor.
    Furnace blower Motor Capacitor Replacement 22

  19. Double check the assembly.
  20. Double-check everything is connected, the fan blades are spinning correctly, and it will be time to reinstall the assembly back into the furnace.
    Furnace Blower Motor Swap

  21. Install the assembly back into the furnace.
  22. Installing it will simply be the reverse of taking it out. The hardest part is often getting it to slide in correctly into the metal tabs.
    Furnace Blower Motor Installation

  23. Tighten the bolt holding the assembly in place.
  24. After getting it back into place tighten it in with the holding screws.
    Furnace Blower Motor Installation 33

    After getting the assembly back in, double-check the fan blades again for proper spinning, you don’t want to damage anything when power is applied, and they spin fast.

  25. Reattach the wiring.
  26. After the assembly is back in place, the wiring can be reconnected. This is where the picture taken earlier comes into play.
    Furnace blower Motor Capacitor Wiring
    If there is a wiring problem, look at the schematic for the furnace and examine the wiring.

  27. Test the blower motor.
  28. Turn the power back on. It is always a good idea to double check everything before turning the power back on.

    Once the power is back on, and the thermostat is set, the furnace should kick on and the blower motor spinning.

Category: Furnace repair

About Aaron H. Benetti

Aaron H. Benetti has worked in the HVAC field since 1991. He began his career as an HVAC installer and later began doing troubleshooting and repairs. Around 2010, he began to write books on HVAC topics, mainly tutorials and how-to information. Currently, Aaron writes many articles and posts for websites as well as books and videos on HVAC topics.

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