Removing the Motor
Turn off all the power. For safety sake it's best to turn off the entire circuit and not just the wall switch. Turn on the wall switch to make sure you have the right circuit breaker turned off. Turn off the wall switch again. I'm paranoid, so I tape the wall switch off while I'm working.
Remove the fan grill. It's usually held in place by a couple of screws and some sort of spring retainer.
Clean the dust off the motor. You should be able to find a model number and brand on the fan housing or on the motor itself. Write down the name of the manufacturer and the model number. Don't order a new motor yet, until you get the old one out. If other parts of the fan are damaged, you might need to replace them.
Unplug the fan motor from its power wires. Write down what color wires on the motor were attached to which wires from the house circuit.
Remove the motor, the attached fan blade and the supporting plate from the housing. A couple of tabs or screws are all that hold the motor in place.
Remove the fan from the motor shaft. This can be difficult. Over time, fan blades can adhere to the fan shaft due to heat and corrosion. It's usually held in place by a screw or is pressed onto the shaft. If you damage the fan, it's not expensive to replace--$3 to $10.
Replacing the new motor
Buy a new motor. Your home improvement store or an appliance store might have the motor in stock or be able to special order it for you. You may get quicker service by ordering it over the Internet. Simply search for the manufacturer or search "bathroom fan motor" and the brand name.
Reattach the fan blade to the motor shaft with the screw or press it into place--whichever way it's designed to work.
Reverse the procedure you used to remove the fan motor. Find the tabs or screw holes and line up the motor with them.
Screw or snap the motor and fan assembly into place. Tighten the screws or make sure the tabs lock into place.
Attach the wires to the motor in the same way your notes say they were connected before. It's best to replace old wire connector nuts with fresh new ones while you're replacing things. Nothing's more frustrating than to get the whole thing back together and realize the old nut came loose. A new 10-cent wire nut can save you a lot of frustration and reassembly later.
Make one last visual inspection inside the fan housing, then snap or screw the grill back into place. Flip on the power and turn on the switch to test the new fan.
Things You Will Need
- Screw driver (Phillips and slot) Pair of pliers Spare screw-on electric wire connector nuts Electrical tape
- Fan blades or the grill can be had for a few bucks. You may even have to replace the entire housing, but avoid it if you can. You may find that an upgrade kit that includes the motor is cheaper than the motor itself. If you have a lot of other parts that are damaged, it may be cheaper to buy the entire fan assembly and cannibalize it for only the parts you need to replace.