A light switch interrupts power going to a light fixture to turn it off. If you flip the switch for your light and the light bulb stays illuminated, the switch went bad. Replacing an electrical switch is one of the easiest places to start learning more about a home's electrical connections. The wires are already cut, trimmed and installed. You simply have to remove the wires from the old switch and install them into a new switch.
Find the breaker box or fuse box in your home and turn off the breaker or fuse that connects to the light fixture. You will know when you have the correct breaker or fuse because the light will turn off. Do not attempt to change the switch with the power still connected because this can result in electrocution.
Remove the screw that holds the cover panel onto the switch housing. This might require a Phillips or regular screwdriver. Place the cover off to the side.
Remove the two screws that hold the light switch inside the electrical box with a screwdriver. Again, this could require a Phillips or regular screwdriver. Pull the switch out of the box. This will straighten out the wires connected to the switch.
Place a piece of tape on each wire and label where each wire connects to each screw or press-fit socket.
Remove the wires from the switch. If the wires screw on, use a screwdriver. If the wires go straight into the switch, use a pair of needle-nose pliers to pull them out of the press-fit socket.
Secure the wires to the new switch. Place each wire in the exact same location as they were when connected to the old switch. Use a screwdriver or needle-nose pliers to attach the wires.
Push the switch into the electrical box and attach it with the two screws. Tuck the wires into the box.
Place the cover onto the switch with the screw and make sure the switch is turned off.
Turn on the breaker or the fuse and then test the switch to see whether it turns on.