To troubleshoot fluorescent light fixtures, test the power supply, check the bulbs and replace the bulb retainers. Fluorescent light bulbs typically have a lifespan of between 8,000 and 15,000 hours.
Improper power flow is one of the most common problems with fluorescent light fixtures. Begin by testing the breaker box with a noncontact voltage tester. Ensure there is power to the output wire and the circuit breaker is on. Next, check the switch for continuity. Turn on the light switch, and test the fixture for power.
If there is proper power flow to the light fixture, the problem could be faulty bulbs. Inspect the end of the bulb for dark sections, which indicate a faulty bulb. The tubes for four-bulb and two-bulb fixtures need to be replaced as pairs.
If the bulbs are not the problem, the issue could be with the bulb retainers. Begin by rotating the bulb to see if it clicks into place. If not, the brass spring clips are faulty and need to be replaced. Next, inspect the clips for burn spots, and replace if any are spotted. Lastly, test each clip for continuity with a noncontact voltage meter, and replace the problem clips, if any.