How to test fluorescent light bulbs?

Repeat the test at the other end of the bulb. A reading outside of this range indicates an open circuit--bad filament--or a short in the filament, and the bulb is no good. To use a continuity tester, clamp the tester lead to one of the pins and touch the tester probe to the other. read more

Step 5 – Check the Ballast. In the event that with a new bulb and new starter, the fluorescent bulb still won’t light up, your best bet is to check the ballast. With a screwdriver, take out the ballast and survey for any oil leaks. Install new ballast if the current one is leaking oil. If it isn’t try to check the system for any loose connections. read more

Test the bulb in a working fixture. Remove the bulb from the fixture in question and test it in another lamp. If the problem lies within the lamp, the bulb should work in a separate fixture. If testing tube lights, be sure to test both bulbs even if only one is out. Currents travel between both tubes and either could be causing the problem. read more