There’s a way to do this for every type of holder we use. The size and shape of the bulbs may vary, and they may be incandescent, fluorescent, halogen, or LED bulbs, but they all have one thing in common: They have to have power coming in, going through the bulb, and returning to the source. They won’t work without that. And, in most cases, you should be able to restore that function. You’ll need a multimeter to do some testing.
How to Test Complete Circuits in On/Off Sockets
How to Test Complete Circuits in Fluorescent Fixtures
This can be done in two ways. The first one involves opening the wiring compartment and testing for 120VAC, hot-to-neutral and hot-to-ground, on the wires coming into it. If there’s a problem there that can be fixed, great. If that checks out okay, though, it’s usually time to replace either the ballast or the whole fixture. One thing to note here is that, unlike fixtures that use other types of bulbs, many straight-tube fluorescent fixtures need to have a good connection to the ground to work properly. That connection should be visible as a green or bare conductor—wire—that’s terminated under a green hex-heat screw near the ballast. Look at it carefully to see if there’s a bare spot behind the wire to allow the ground to make good contact. The other test is to use your multimeter to test the power on the output side of the ballast. Since different ballasts have different output characteristics, you will need to read the information on the label on the ballast in your fixture to determine the settings you need to use.
