How to Repair Fluorescent Light Fixtures

Repairing fluorescent light fixtures is usually a simple procedure. Sometimes it is less expensive to buy a new fixture than to repair the old one. A simple process of elimination will locate the problem. To make the repair is just a matter of replacing the broken part. A simple comparison of the cost of the replacement part to a new fixture will let you know the best way to repair the fixture.

Things You'll Need

  • Bulb that is not blown
  • Wire nuts

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How to Repair Fluorescent Light Fixtures

Determine if the circuit breaker is switched off or the fuse is blown. If the circuit breaker or fuse is blown fix it before proceeding. It may have nothing to do with the light fixture.

Check the condition of the bulbs. Bulbs that are dark on the ends are signs they are old and either blown or nearly blown. If the bulbs are flickering that could be the bulb or something else. Replace the bulbs with known working bulbs. The majority of the time this will solve the problem. Rotate the bulbs so they are clearly making good contact on the ends. If this does not fix the problem you’ll have to decide if you want to replace the ballast or replace the entire fixture.

Take the cover off of the area behind the bulbs. The ballast is the rectangular device with several wires connected to it. Take down the model number and check a local supplier for the cost to replace it. Often the price to replace the ballast is higher than a new fixture. Carefully compare the exact ballast that you need. There are many different sizes available any several are very similar to each other but configured differently.

Replace the ballast by reconnecting the wires exactly as they were originally connected. Red to red, black to black, white to white and don’t forget the ground wire. Most ballast has an instruction sheet that comes with them in the box. Wire nuts are usually supplied also. Defective ballast usually causes the lights to flicker.

Replace the bulbs with known working bulbs and test the light.

Tips & Warnings

  • Older fixtures may have additional parts.
  • Older fixtures should be replaced with newer energy efficient models.
  • Always take safety precautions and wear proper safety equipment when working with electricity.


  • Ed English; Author; English Explorers LLC; Lawrenceville, Georgia
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