The fastest way to test a fluorescent tube is with a multimeter set to continuity mode. If either filament is broken, the tube is dead. If you don't have a multimeter to use, a simple coin cell battery holder with leads will let you know. To test a fluorescent light bulb, observe any of the following: flickering light, low brightness, buzzing sound, delayed start, and fading color and light variation. Multimeters provide. Can you test an LED light with a multimeter? Yes, you absolutely can test an LED light with a multimeter! It's a straightforward process that helps you figure out if your LED is working or if it's the source of a problem in your circuit. This guide will walk you through LED testing using a.