There are different methods of troubleshooting a malfunctioning fluorescent light, depending on the cause of the problem, according to the fluorescent lighting system guide written by Frank Durda IV. Issues with fluorescent lights often occur with pre-heat fixtures.
The most common problem among fluorescent lamps is a lamp in a fixture that does not light or flicker at all, according to Durda. In this case, ensure that the electrical power for the pre-heat fixture is turned on, particularly if all lamps in the fixture fail to light. If the fixture only has one lamp, check if the correct starter is secure in its socket and the lamp is properly placed in both lamp holders. Additionally, make sure that you have installed the right type of starter. FS-2 starters are recommended for 18-inch and 24-inch lamps. Replace the lamp and starter if your fixture has a single lamp and the lamp or starter is worn out. Try changing the ballast if the fixture contains only one ballast. If it has several ballasts, the problem is likely a low supply voltage or lack of electricity. Try using an AC voltmeter to confirm that sufficient electrical voltage is reaching the ballast.
For recently installed or fixed fixtures, the cause of the problem is possibly a wiring error, notes Durda. Check the diagram on the ballast that shows the proper wiring, and compare the fixture's wiring to the diagram.