Turn off the power for the furnace at the main circuit breaker.
Locate the Fasco blower unit for your furnace. In most cases, this will be on the interior side of the heating unit, typically in the attic or a heating closet.
Remove the screws on the access panel on the blower housing. These may be hex-head or Phillips screws or bolts. Set the panel aside.
Unplug the blower motor from the wiring harness by disconnecting the plug-in type connectors that hook into the furnace
wiring.
Loosen the screws on the blower housing, using the screwdriver. Pull the blower housing apart after the screws have been removed.
Slide the impelller off the Fasco impeller shaft.