Fixing a pull-chain light fixture can save you both money and time. Instead of purchasing a new fixture, a new pull chain will only cost a dollar or two and will require a minimal amount of time. The pull chain is connected to a toggle switch so the light can be turned on and off. Many ceiling lights use this type of switch; however, the chains that come with these fixtures tend to be thin and over time will break.
Find the circuit breaker, or fuse, controlling the power to the light fixture and turn it off. If the chain broke with the light on, cutting power will be easy to verify. If it broke with in the off position, remove the bulb and use a touch-type voltage tester on the fixture. Insert the tester into the socket and if the line is active, it will light up or beep.
Disconnect fixture from mounting bracket. Usually it is nothing more than a couple of Phillips-head screws, but particulars will depend on the style of the fixture. Slowly pull the fixture away from ceiling.
Disconnect wires connecting fixture to ceiling. A wire nut will cover the connections. Twist the plastic nut counterclockwise and remove it. Remove any electrical tape as well. Untwist the wire connection, freeing the fixture from the ceiling.
Turn the end cap counterclockwise until the cap slides over the chain and off the fixture, giving you access to the wires that connect the pull chain to the fixture. Disconnect these wires and remove old pull chain.
Insert the new pull chain and replace the end cap holding the chain in place. The light fixture itself remains free from the ceiling, allowing access to wiring.
Connect a wire from pull chain switch to black wire from fixture. Secure connection with electrical tape.
Take the other black wire from pull chain switch and connect it to the black wire from ceiling. Next, connect white wire from light fixture to white wire from ceiling. Wrap connections with electrical tape.
Re-mount the light fixture onto ceiling bracket and replace the light bulb. Turn circuit on, or reinsert fuse, and test the pull chain.