Most of the time, problems with a bathroom fan involve a failed motor, a problem the homeowner fixes by replacing the old motor with a new one. According to The Family Handyman, replacement motors are available even for fans that are several decades old. While replacing the motor costs about the same as replacing the unit, it involves much less work.
Before beginning the job, turn the circuit breaker controlling the fan to the off position. Pulling the cover down on most fans allows it to drop for access. The springs, located on opposite sides, press together to allow complete removal of the cover. A vacuum helps to remove the accumulated dust, allowing the owner to determine the manufacturer and model number of the fan.
In most fans, an electrical plug provides power to the fan. Pulling it from the outlet disconnects the power and removal of the retaining screws allows the removal of the fan. Installing the new one requires reversing the steps. When the power is back on, the replacement fan motor should operate perfectly.
If there is no vent cap over the bathroom, the fan potentially does not have a vent. This allows moisture to build up in the attic. Homeowners should consider installing tubing and a vent cap to ensure moisture does not encourage rot.