Fluorescent Lighting Repair

This Fix-It Guide tells how efficient fluorescent lighting works, what often goes wrong, how to identify a fluorescent lighting problem, and what parts and tools you will need to fix it. It then gives step-by-step instructions for fluorescent lighting starter replacement, ballast replacement, and socket replacement. Because they are simple in operation, fluorescent lighting systems are also easy to repair.

How Does Fluorescent Lighting Work?

 Fluorescent Lighting Repair

Fluorescent lighting typically is easy to work on with the exception of smaller units that may not allow access to internal parts. If the bulb is okay, but the unit still doesn’t work, check the electrical cord and replace the unit as needed.

A fluorescent lighting fixture converts electricity into light by making gas inside a phosphor-lined tube glow. The fluorescent fixture is either wired into the house electrical system or plugged into a nearby receptacle. Electrical voltage is delivered to the fluorescent tube by a component called the ballast. When the fixture is turned on, more electricity is needed than during normal operation, so a starter tells the ballast to boost the voltage. Once running, the starter turns off and the ballast maintains the voltage to a lower operating level.

What Can Go Wrong with Fluorescent Lighting?

Any of the main components of a fluorescent lighting fixture can be the source of problems. You may need to learn about fluorescent tube replacement, starter replacement, ballast replacement, or socket replacement. Problems with fluorescent lighting systems are relatively easy to diagnose and solve.


Be especially careful when handling fluorescent lighting tubes. They are quite fragile and contain phosphor and inert gasses. Don’t drop them or let them hit a hard surface!

How Can I Identify a Fluorescent Lighting Problem?

  • If the lamp will not light at all, make sure power is on, then try replacing the fluorescent tube. You can also test the electrical cord.
  • If the light still does not work, try replacing the fluorescent lighting starter (see below), then the ballast (see below).
  • If the lamp glows dimly, the cause is either a defective tube or starter.
  • If the ends of the fluorescent tube light, but the middle is dim or dark, the starter or the tube may be defective.
  • If the light flickers, the tube may be burning out, or the starter or ballast may be defective.
  • If the fluorescent light repeatedly flashes on and off, the tube or the starter may be defective.
  • If the socket doesn’t firmly hold the tube, first make sure that the pins are straight. If the pins are not straight, the socket may need replacing.

Fix-It Tip

Because the starter sends high voltage to fluorescent tubes when starting up, tubes wear out faster if they are turned on and off excessively.

What Do I Need for Fluorescent Lighting Repair?

Most replacement parts for fluorescent lighting fixtures are available at larger hardware and lighting stores. The tools you’ll need to fix a fixture include these:

  • Screwdrivers
  • Wrenches
  • Multimeter

What Are the Steps to Fluorescent Lighting Repair?

Replace a fluorescent lighting starter:

  1. Turn off power to the fixture.
  2. Lift the fixture diffuser or cover (if installed) and tubes to access the starter, a round plug-in component attached near the larger ballast.
  3. Twist out the old starter and replace it with one that has the identical part number and rating. A hardware clerk can help you select the proper replacement.

Replace a fluorescent lighting ballast:

  1. Turn off power to the fixture.
  2. Remove the diffuser, tubes, and cover plate.
  3. Identify the ballast, a large heavy component often near the center of the fixture. Disconnect wires to the ballast and disconnect the ballast from the fixture. Test with a multimeter.
  4. Replace the ballast with one of the same rating as the old unit. Mount the new ballast and reconnect wires in the same manner as they were disconnected.
  5. Replace the cover plate, tubes, and diffuser.
  6. Plug in or turn on the circuit to verify that the fixture is working.

Replace a fluorescent lighting socket:

  1. Turn off power to the fixture.
  2. Remove the diffuser, tubes, and cover plate.
  3. Disconnect wires from the socket.
  4. Disconnect and remove the socket.
  5. Replace the socket with a duplicate unit.
  6. Replace the cover plate, tubes, and diffuser.
  7. Plug the light in or turn on the circuit to verify that the fixture is working.

Fix-It Tip

A ballast is the most expensive component in a fluorescent lighting fixture. If it requires replacement, check the price of a new fixture; it may be less expensive. Because the ballast is a wire transformer you may be able to recycle it as metal.