How to Replace Your Furnace's Blower Motor

When undertaking a HVAC project, you should be very careful and follow all safety procedures to

avoid show, fire and cutting yourself. To replace the blower motor on your furnace first turn off the power to the furnace, next rotate the knob securing the blower chamber panel and pull the panel off. Now loosen the screws to release the humidifier wires if applicable. Note the orientation at the thermostat wires, then loosen the screws to detach them. Now cut the control board wire harness tie. Then remove the screws securing the blower assembly support bracket, and carefully slide the assembly out of the furnace. This will be heavy.

Note the orientation of the motor wires on the control board then disconnect them. Now disconnect the wires from the run capacitor. Remove the screw to release the motor grounding wire, and set the run capacitor aside. Use a wrench to loosen the set-screw to release the blower wheel from the motor shaft. Rotate the assembly and use a 3/8 inch socket to remove the screws securing the blower motor mounting bracket. Pull the motor and bracket off and make sure to mark where the old motor is positioned on the bracket. Now loosen the bolts on the side of the bracket and remove the old motor.


You're now ready to install the new blower motor. If you are not comfortable finishing this project on your own, call a HVAC company for assistance. Properly position the new motor in the mounting bracket. Then tighten the bolts to secure it in place. Insert the motor shaft into the center of the blower wheel and align the mounting bracket on the blower wheel housing. Replace the mounting screws to secure the new blower in place. Center the blower wheel in the housing making sure the flat side of the motor shaft aligns with the set-screw then tighten the screw. Reposition the run capacitor in the support strap. Align the new motor grounding wire and secure with the screw. Connect the appropriate wires to the capacitor. Connect the remaining motor wires to the appropriate terminals on the control board. Use a zip tie to tighten the wires. Now aligned the blower assembly on the support rails and slide it into position. Replace the screws to secure the support bracket. Again use a zip tie to remove any slack. Reconnect the thermostat wires and tighten the screws to secure. Reconnect the humidifier wires if applicable for your furnace and tighten the screws. In the blower chamber panel and rotate the knobs to secure. Finally restore power to the furnace and check to make sure that it is working properly.