How to Replace the Furnace Blower by DIY? (9 Steps)

Is it hard to replace a blower motor?

Replacing a furnace blower motor ranges from fairly easy to a bit challenging based on the type of blower and the furnace design.

But for each type, the process is straightforward. If you’ve got DIY or HVAC experience, you should be able to accomplish the task without too much trouble.

If you don’t have experience, these comprehensive step-by-step instructions below will help you successfully accomplish the job.

Cost to Replace a Blower Motor

The labor cost for professional replacement of a blower motor can be between $100 and $300, so replacing your blower motor yourself is a worthwhile task.

* Please note that this is a guide and may not provide all of the details for every DIY blower motor replacement.

What to Know Before Purchasing a New Blower Motor

When replacing your furnace blower motor, you will need to purchase a new unit that exactly duplicates the old motor in type, size and design. It starts with knowing whether your old motor is direct drive or belt driven.

Specifications to Know: You will also need the motor diameter, horsepower, speed in RPMs, voltage, amps, fan speed or speeds, mounting method, and shaft size. The model and serial numbers will also be helpful. Your old blower has a label that lists this information.

Does it have to be the same brand? No – just the same specs. There are several third-party manufacturers that make quality replacement blower motors that match OEM specifications.

The Blower Wheel and the Capacitor

It may be a good idea to replace the blower wheel at this time, especially if it is bent or damaged. HVAC professionals recommend replacing the capacitor when you are replacing the blower motor. Make sure you also purchase an exact match for the capacitor. Capacitors are cheap and easy to replace.

Some new blower motors come with a compatible capacitor as part of the assembly.

How Long Will the Job Take?

An experienced HVAC technician will take about 30 minutes to remove the old blower motor and about and 60 minutes to install the new motor, adjust it, if it’s a multi or variable speed motor, and test run the furnace. Installing a new blower wheel or cleaning the old wheel will only take a few additional minutes.

Since you may not have the experience of an HVAC tech, expect to spend around twice the time. It’s always better to take your time and make sure the job is done safely and correctly.

Helpful Tools

Following are recommended tools that will make the job of changing a blower motor much easier:

  • Smartphone for taking pictures
  • Cordless drill or screwdriver with a flexible shaft bit holder
  • Magnetic, pivoting flashlight
  • Cut resistant stretch gloves – to prevent being cut by sharp sheet metal edges
  • Magnetic tray to hold screws

Prep Step 1: Keep Track of the Wires

When replacing a blower motor, you will be removing or disconnecting a number of wires. In some cases, you may need to cut wires. If you have a smartphone, take a picture at each step of the process, before disconnecting or cutting wires, then you will have a visual record of how to put everything back correctly. If you don’t have a smartphone, note wire colors and where they are connected as you proceed.

Prep Step 2: Get Started Safely

Before beginning, shut off the power and, if it’s a gas furnace, close the gas valve.

Step by Step Blower Motor Replacement

Not all furnaces have the same cabinet design and blower location or type. Our instructions below will provide you with the basics. There are a number of online videos and tutorials, so you should be able to find one that is specific to your furnace if needed.

Step 1: Remove the Panels and Locate the Blower Assembly

The blower motor assembly is normally located in the lower part of the furnace. Remove the lower furnace panel, in some cases you will have to remove the upper panel first. In belt driven blower motors, there may just be a blower cover on the lower portion of the furnace.

Step 2: Remove the Blower Assembly

Most likely, there will be a control or circuit panel in front of the blower assembly that will need to be removed. Note, or take a picture, of the wire colors and placement, then disconnect only the wires necessary to move the control panel out of the way. There should be 2 to 4 screws in the top of the control panel holding it to the furnace cabinet. Remove the screws and move the control panel to the side.

Once the control panel is out of the way, remove the screws holding the blower assembly. These screws are located at the top front of the assembly on most furnaces. Slide the blower assembly along the tracks that hold it in place and out of the furnace.

If you’re replacing the entire assembly, then you’re almost done. Connect and slide the new assembly into place. Fasten it, and reposition the control/circuit board.

Step 3: Remove the Blower Motor

Once the assembly is removed, lay it on the side with access to the drive shaft and loosen, but don’t remove, the shaft holding screw. Free the wheel from the drive shaft by using a non-toothed wrench so no griping marks will be made on the shaft, otherwise it will be very hard to remove the motor. Hold the shaft with the wrench and spin the wheel. If the wheel won’t spin, apply lubricant around the shaft and retry after a few minutes.

Once the wheel is spinning freely, flip over the blower assembly and remove the screws holding the motor brackets.

Pro Tip: At this point, you may need to cut the wires. Again, take a picture or make notes, so when reassembling the ff you can connect the proper wire ends with wire nuts.

Lift the brackets and motor from the assembly. Remove the screws holding the mounting bracket to the motor, again taking note of where the screws are placed along the bracket. Some mounting brackets have multiple screw holes to accommodate various size motors. Remove the mounting brackets from the motor.

Now is the time to either replace the blower fan or give the fan a good cleaning. A very dirty fan can affect the functioning of the blower motor.

Step 4: Replace the Blower Motor

Fit the mounting brackets around the new motor, replace the screws, and insert the motor into the blower housing. Line up the holes in the ends of the brackets with the screw holes in the housing. The new blower motor will have a number of wires attached to it. Be sure to point the wires outward and toward the control panel. Reattach the grounding wire, most often green, to the motor housing. Make sure the ground wire is placed in a way that it won’t fall between the motor and the fan.

Step 5: Adjust the Blower Motor

Once you have the new motor in place, flip the housing on its end and adjust the wheel so that it is centered on the shaft. Retighten the set screw on the shaft to hold the blower wheel and motor in place. Test it to make sure the wheel spins freely.

Step 6: Replace the Capacitor

When you replace your blower motor, it only makes sense to replace the capacitor. Running a new motor on an old capacitor can damage the new motor if the old capacitor is worn and not working at maximum capacity.

Pro safety tip: Removing a capacitor can be a shocking experience! These very useful devices store up a charge to “kick start” the blower motor the next time it starts. This saves wear and tear on the blower motor and is sometimes necessary to get the motor humming. So, you definitely want to discharge the capacitor before removing it – a simple technique taught in this Pick HVAC DIY Guide about AC capacitors, but the information and how-to’s apply to a furnace blower motor capacitor too.

Where is the capacitor located? The capacitor is normally located on the side of the blower housing. Simply loosen one side of the capacitor brackets by removing the screws, slip out the old unit and insert the new unit, and then replace the screws. Find the 2 wires on the motor that connect the capacitor to the motor, usually brown or purple, and attach them to the capacitor. Insert the new capacitor into the bracket, replace, and tighten the screws.

Pro Tip: As with the blower assembly, it will be helpful to take pictures of the old capacitor installed, including the wiring, before replacement.

Step 7: Replace the Blower Assembly

To slide the blower assembly back into the furnace, you will need to locate the tracks inside the furnace cabinet. The lips on the upper edges of the blower assembly will slide into the tracks when you lift and push the assembly into the furnace. Replace the screws at the top front of the assembly.

Step 8: Replace the Control Panel

Usually, the control panel has clips on top allowing you to slide in the panel and line up the screw holes. If you’ve had to cut the wires, strip the wires and use wire nuts to securely connect them. Be sure to match the wires color to color. If the wires are in the way, you can use a zip tie or electrical tape to keep them organized.

Step 9: Button it Up and Test It

Replace the furnace panels, turn on power to the furnace, open the gas line and restart the furnace.

If all went well, and it should with the above instructions, your furnace will be back in business cranking out heat in winter and assisting air conditioning in hot months.

Here is a video showing blower motor replacement incorporating the instructions above.

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