These F32T8 kitchen light bulbs stopped working, so I replaced them with these bulbs. After I replaced it, the lights turned on fine the first time. However, the lights no longer turn on. I've checked that the new lights are compatible with the old one and I have also checked the circuit breaker. How can I fix this? Thank you.

Additional: Immediately after the light bulb change, the light was on for 1+ hour. However, once I turned it off, it did not come back on. Just now, the light turned on when I was flipping the switch. After that, it does not come back on again.

Not sure of the model of the light fixture

  • 2
    Are you certain that it was the bulbs that went bad in the first place, not the fixtures themselves? If the light went out because the fixture died, no amount of replacing bulbs will bring it back.
    – FreeMan
    Jun 4, 2020 at 11:31
  • Honestly I have no idea. The light turned on when I replaced the bulbs so I am even more puzzled. Would the fixture most likely be the problem? Would you recommend getting a technician or is it easy to DIY? Jun 4, 2020 at 12:03
  • I just tried turning the lights on now and it turned on, only to fail to work the second time. Is it the fixture that is messed up?/ Jun 4, 2020 at 12:06
  • For added clarity: It seems that the lights will turn on, however, when turning them off then on they fail to come on the 2nd time? When you turn them on, do they stay on? Do they stay on for a certain amount of time (10 seconds, 1 minute 10 minutes)? Are you flipping the switch off then right back on for the "2nd time", or is there some delay between the off/on? Is it just one fixture or are there many? Please edit this info into your original post so others can help with the diagnosis, too. Include the brand/model # of the light fixture(s) if at all possible.
    – FreeMan
    Jun 4, 2020 at 12:34
  • Oh, and welcome to Home Improvement! :) Once you've made your edits, you can pass some time by taking the tour and browsing the help center to see how the SE sites are different than most standard internet forums - this will help you get the most out of the site.
    – FreeMan
    Jun 4, 2020 at 12:35

2 Answers 2


Sounds like a bad ballast. Ballasts do not live forever and need to be replaced from time to time.

  • Just to confirm, this applies even when replacing standard fluorescent tubes with more modern LED tubes?
    – FreeMan
    Jun 4, 2020 at 12:45
  • I replaced them with the LED tubes today. Jun 4, 2020 at 12:57
  • Depends on the tubes. In this case, these are LED "tubes" that need a ballast to work - i.e. they are NOT "direct wire" type replacements.
    – Ecnerwal
    Jun 5, 2020 at 0:37
  • I haven't replaced a ballast in 20y. New fixture time.
    – Mazura
    Sep 8, 2021 at 10:31

The evidence isn't all in, but I'm inclined to believe it has a bad ballast. The ballast is an electronic module inside a fluorescent light that regulates current to the light. It's essential for fluorescents.

There are 4 options for lamps.

  • New Real Fluorescent. This old tech has leapt forward amazingly, all the old annoyances are gone, and it's the best light quality (Color Rendering Index) on the market. Many random box-store fluorescent tubes are 90 CRI (near perfect). Many LED "tubes" won't even state their CRI. It's also exceedingly reliable stuff. I've installed a hundred with zero failures.

  • LED replacement "tubes" come in three kinds. First, the kind just like yours (called "Plug-n-play") that requires the old fluorescent ballast to be present and working. One one hand, you must maintain that ballast, which is a bit silly. On the other hand, it lets you rollback to real fluorescent once you realize that LEDs have a lot of issues.

  • LED "Direct wire" aka "Ballast Bypass" - this requires that you hack into the fixture to bypass the ballast altogether and shoot straight 120V mains current to the ends of the tube sockets. And different LED tubes do this 2 ways: The better ones want hot and neutral on opposite ends. The cheaper ones want hot and neutral at the same end - it's 0.5 cents cheaper to build, but makes it a nightmare to install on instant-start fixtures.

  • LED "Universal" - these will work either with a ballast or ballast-bypass. They are double-ended, so if you do direct-wire, they'll be easier to wire into any fluorescent fixture.

There's no way out of this except rewiring

Given the bad ballast, you will be forced to rewire something. A wiring diagram here may be useful.

Replace the ballast with another ballast.

At that point you can run either Real Fluorescent (try the 90+ CRI tubes) or plug-and-play LEDs. This is a 2-step process:

  • identify your existing wire colors from the ballast. If you have 2 yellow 2 blue 2 red, you want a Rapid-start or Programmed-start ballast. If you only have 1 red 2 blue, then you want an Instant-start ballast.
  • Now shop for a ballast that supports 2 x F32T8 (which will be easy, since most do that). If you think the room has too much light, someone on eBay is selling a fantastic but very dim (only 71% of normal light) ballast for $5 each.
  • Then simply cut the wires at the old ballast, swap ballast phyiscally, and hook up wires by number - 1 yellow to 1 yellow, 1 red to 1 red, etc. I use blue (small) wire-nuts for this.

Or, rewire the fixture for direct-wire LED.

Then you are married to LED going forward. And you need to make a decision about "opposite-end wiring" or "same-end wiring".

  • Opposite-end wiring. The yellow, red or blue wires going toward one end all get spliced to hot. Those wires going to the other end all get spliced to neutral.
  • Same-end wiring, AND your old wiring is Rapid or Programmed Start (2 wires per socket). There you hook hot to 1 yellow wire, neutral to the other yellow wire, and individually cap off all other wires.
  • Same end wiring, AND your old wiring is for an Instant-Start ballast: go to the store and buy non-shunting lampholders, dismantle the fixture even further--- oh forget that, return the same-end LED and get an opposite-end LED.

Or, tear the fixture off the wall altogether, give it away on Craigslist, and get a whole 'nother fixture.

  • Are ballasts really hard-wired in? I seem to recall that the last time I replaced a ballast (I think I've only ever replaced 1), it was a push-and-turn type module that fit similarly to the way the actual fluorescent bulb fits in.
    – FreeMan
    Jun 4, 2020 at 15:41
  • @FreeMan Are you referring to a "starter"? A small cylindrical unit about the diameter of a nickle and about an 1" or so long. They are for very old school fluorescent fixtures. Jun 4, 2020 at 16:17
  • @GeorgeAnderson it's entirely possible that what I'm referring to. I thought it was a "ballast", and could have sworn that's how the package for the replacement was labeled. That's why I asked!
    – FreeMan
    Jun 4, 2020 at 16:21
  • 1
    @FreeMan could be. Florescent fixtures aren't really all that complicated. Newer ones are just a ballast and the tubes. If they don't work, one or the other is bad. Older ones have "starters". My mom had a very decorative (think 50s art deco) florescent fixture that was failing. It was well worth saving. So I gutted it, replaced the ballasts with modern ones and new bulbs (tubes). Been fine ever since. This was before LED tubes became available, or I would have gone that route. Jun 4, 2020 at 16:46
  • 2
    Starters and "F32T8-as-efficient-replacement-for-T12" never co-existed. Jun 4, 2020 at 18:08

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