How to Replace a Fluorescent Light Bulb

First step? – Check the fixture for other problems

When fluorescent bulbs go bad, there may be a problem with the fixture. Learn simple repairs for the most common problems.

By the DIY experts of The Family Handyman Magazine

Servicing a fluorescent light

Fluorescent light fixtures are durable and virtually maintenance free, but occasionally service and repair are required. If you’ve got a fluorescent fixture that doesn’t light up, flickers on and off, or won’t hold a bulb, we’ll show you how to troubleshoot the problem. Replacement parts are easy to install and can be found at home centers and hardware stores.

If the fixture won’t light up at all, it may not be getting power. Check the circuit breaker or fuse box, and reset or replace the necessary equipment.

Fluorescent light bulbs typically last many years, but when one flickers on and off, or the end turns light gray to black in color, it needs to be replaced. Photo 1 shows a bad bulb and how to replace it. Replace the bulb with the same size bulb.

Another common problem is cracked sockets, caused by bumps from other objects or stress from removing a bulb. Shut down power to the light, remove the bulbs and then open up the fixture to gain access to the broken socket (Photo 2). There will be two or four wires coming into the socket. Keep the wiring straight by swapping wires from one side of the socket at a time as shown in Photo 3.

If the fixture still doesn’t work, then the ballast is probably shot. The ballast boosts the incoming voltage to start the tubes, and then regulates the current to provide continuous light. Ballast replacement can cost as much as a new fixture, so buying a new fixture may be a better investment.


Unplug the light before making repairs, or turn off the circuit at the main panel.

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Wire stripper/cutter

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Replacement bulb
  • Bulb socket

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