Most light fixtures have decorative parts and electrical parts. The decorative parts include the globe and all the shiny tubing and other embellishments that make the fixture nice to look at. The electrical parts consist of sockets and their wiring. Sockets can fail because they simply wear out and no longer make a good connection with the bulb, or they can overheat (usually caused by a high-wattage bulb) or short out. Fortunately, if a socket fails, you can take it out and replace it, so your beautiful decorative fixture works like new again.
Choosing the Right Replacement Socket
Light bulb sockets come in a huge range of types and styles and are designed for specific uses and bulb wattages. Replacing the socket on an outdoor or indoor fixture is similar, but it's important to use the right socket for the fixture. Outdoor sockets are generally more robust than indoor sockets and often have special features for moisture- or weather-resistance. For any type of fixture, choose a socket that looks identical (or nearly identical) to the original and has the same maximum wattage rating.
Tools and Supplies You Will Need
Turn Off the Power
Turn off the power to the circuit that you'll be working on by switching off the appropriate breaker in your home's electrical service panel (breaker box).
Test for Power
Use a non-contact voltage tester to check for power in the light socket. Remove the light bulb from the bad socket, and touch the probe of a non-contact voltage tester to the metal tab inside the socket. Flip the light switch and test the socket again. The tester should not light up for either test.
The reason for testing with both switch positions is because some switches (like three-way switches) can be on or off in either position.
Remove the Globe
Remove the globe from the fixture. The globe may be held by internal clips, screws on the outer ring of the fixture, or a retainer nut on the bottom of the globe. Hold the globe in one hand while loosening the screw or nut with the other. Set the globe aside for now.
Loosen the Fixture and Test for Power
Loosen or remove the mounting screws securing the fixture base to the electrical box in the wall or ceiling. Carefully pull the fixture away from the box without touching any wires. Test for power again by touching the probe of the voltage tester to each of the fixture wires and all of the wires in the box. The tester should not light up; if it does, return to the service panel and turn off the correct breaker, then retest the wires to confirm the power is off.
Disconnect the Wiring
Twist the wire connector (wire nut) counterclockwise and remove it from each set of wires, then separate the wires. Disconnect the ground wire from the box or fixture mounting strap, as applicable. Take the fixture down and place it on your workbench or table. Pull the black and wire wires from the bad socket through the hole in the fixture so that the socket can be removed.
Remove the Socket
Look inside the socket and locate the Phillips screw (or screws) holding the socket to the fixture. Alternatively, the socket may be held by a retaining nut at the back of the fixture or bulb housing, or there may be a screw and a nut. Remove the screw or nut with a screwdriver or pliers, as applicable. Remove the socket from the fixture, but keep the screw and/or nut in case you need it for the new socket.
Install the New Socket
Fit the new socket into the fixture in the position as the original, and secure it with the screw and/or nut. Be careful not to tighten too much, as sockets can be fragile.
Reinstall the Fixture
Hold the fixture back up to the wall or ceiling box and connect the wires as before, using the same wire nuts. Black wires tie together under one wire nut, and white wires tie together under another. Also re-connect the ground wire, as applicable. Mount the fixture with its mounting screws. Be sure that no wires are protruding from the fixture base. You don't want to pinch an electrical wire.
Clean and Install the Fixture Globe
Clean the globe (this is convenient while it's down) and reinstall it onto the fixture. Screw a light bulb into the new socket.
Turn On the Power
Turn on the breaker in the breaker box and test the fixture for normal operation.