How to Change the Rotation on a Furnace Blower Motor

Shut off the furnace at the breaker switch on the side of the unit or the household circuit breaker. Wait until the furnace cools.

Take out the slotted bolts in the bottom cover plate on the side of the furnace, using a screwdriver. Pull off the plate and set aside. The blower motor is the cylindrical unit at the bottom, bolted to a stabilizing bracket.

Wipe the side of the motor to remove grime and dust, if necessary, so you can inspect the specifications printed on the housing. In most cases, if the motor is reversible, this will be listed on the side of the housing. If not, check the owner's manual or write down the brand and model number of the motor to check with the manufacturer. Do not proceed until you have verified this information. If the motor has a switch control to change the rotation, simply turn the switch. If not, continue with rewiring the motor.

Follow the path of the two wires that connect to the spade terminals on the motor. These wires are typically either orange and yellow or red and black. Each has a spade connector on the end that attaches to the motor terminals.

Grip each spade connector with pliers and pull it off the motor terminals. Do not pull by the wires.

Switch the wire connections on the motor terminals, for example, connecting the black wire to the motor's red terminal and vice versa.

Replace the side panel and secure it with the screws.

Switch on the furnace.