It's irritating when you walk into a room and flip a light switch and nothing happens. It's even more frustrating when you don't know where to begin. It could be a problem with the switch itself or a problem with your home's electrical wiring. If you find yourself in this situation, there are some common problems with light switches that can be easily diagnosed.
Determining the Problem
The first step is to figure out whether there really is a problem with your light switch. Unless there is an apparent problem with the switch (sparks, buzzing nose or hot to the touch, for example), the problem may be something else. Check that all light bulbs are working and tightly screwed in to their sockets. In some circuits, one bad light bulb can cut off power to other lights in the room, so it's important to go back and check.
Checking the Breakers
If all of the bulbs are fine, unplug all of the appliances in the room and check the breaker box. Try flipping the breaker to that room and the master switch a few times to see if your power returns. If you're not sure which breaker runs the light switch, try each breaker one at a time. If you're still not getting any light, it's time to take the switch out of the wall. If flipping the breaker works, it could mean that too many appliances are plugged in and are overloading the circuit.
Before removing the light switch from the wall, disconnect power to the switch. Again, if you don't know which breaker runs the switch, turn off each breaker, even the master switch. If you need light to work, a small flashlight works just fine. It's better to work in the dark than to get zapped.
Removing the Switch
Once there's no power to the light switch, you can safely remove the light switch from the wall. All you'll need is a screwdriver, usually a flat head. First, remove the plate cover by loosening the mounting screws. You'll see the actual switch inside. Remove the switch by loosening the screws at the top and bottom of the mount. Gently pull on the switch. It should come right out of the wall.
Check the Connection
First, check the wires to the switch. Over time, the screws that hold the wires in place can come loose or corrode. The wires and the wire screws must be clean and snug against each other. No wires in the switch should touch any metal other than the screw.
Check the Circuit
If the connection on the switch is fine, test the circuit. You'll need a screwdriver, a pair of needle-nose pliers, a wire cap and an electrical tester. Use the tester to see if the wires are "hot," or carrying an electrical current, by touching its tips to the screws on the switch. If there's no power, loosen the screws holding down the wires and gently pull the wires out. Straighten them with the pliers and then twist them together using the cap. Once they are twisted snuggly, turn on your breakers. If the light now works, you have a bad switch.
Buying a new switch
Luckily, a new switch is cheap; you'll pay as little as $1 at some hardware stores. Buy a switch that matches the old light switch. Some light switches are more complex and operate on a different circuit system. To be safe, bring the old light switch with you to the hardware store and ask an associate to help you pick one out.