Wiring a timer on a bathroom fan can easily be completed in under an hour. Turn off the electrical circuit at the main breaker box before beginning. Test with an electrician's wire tester to make sure the power is off.Continue Reading
Unscrew the switch and switch cover from the wall. Disconnect the wires, using a wire nut to keep track of them.
Using the measurements for a double work box, mark the wall. Use a leveler to make sure the marks are square. Cut the hole using a utility knife.
Pull the wires through the double work box, with one set of wires to connect to the new switch and one to the new timer. Connect each set of wires to the new switch and timer following the manufacturer's instructions.
Line up the toggle switch for the light and the shaft for the timer with the switch cover. Cover the double work box by screwing on the switch cover, attaching the timer plate and knob. Turn the electrical circuit back on at the main breaker box. Test the timer and switch to ensure proper installation.