I searched for similar issues, but didn't find one exactly like I am experiencing. I recently replaced four old light fixtures with LED light fixturess in an existing room. I used these:


In addition, I replaced 2 older dimmer switches with LED compatible ones.

The install was very easy. Everything worked right away. I'm not sure if the problem happened the next day or if it was good for a couple of day, but now when I turn the lights on first thing in the morning 3 of them light up right away and the 4th does not. After 30-60 minutes the light comes on and works fine for the whole day. This is the same every morning.

I assumed the LED fixture was bad so I ordered a single replacement and installed it. When I installed it it worked right away. However the next morning it didn't come on again. So I don't think it is a problem with the light.

If the switch was the issue I don't understand why it would only affect the one light. The other 3 always work right away.

I'm not sure what to try short of talking to an electrician.


This morning, I turned on the lights at 8:10 and it is 10:51 and the light still hasn't come on. Maybe this is getting worse or is completely not working now. I am going to buy a simple light switch and switch out the dimmer to see if it makes a difference.

  • 1
    Try swapping the dimmer for a regular switch (for testing purposes) - or check the documentation for the dimmer switch to see if there are adjustments to the dimming range. While I have not had that extreme of a case, when turning on sets of LEDs on a dimmer with the dimmer set low there are noticable delays and different delays between units - but on the order of seconds, not minutes or hours. Those can be reduced by setting the lowest dimming level higher, or by turning the lights on bright, then dimming. Your described problem is odder.
    – Ecnerwal
    Commented Sep 17, 2020 at 20:42
  • 1
    If you're up for the labor, you could try moving a "works fine" unit to the "problem spot" - and a "problem" unit to a "works fine" spot - if the problem stays in the same location rather than following fixtures, it might be some weird wiring issue?
    – Ecnerwal
    Commented Sep 17, 2020 at 20:44
  • 2
    I bought a replacement LED and put it in the "not working" spot and it behaved exactly like before I replaced it, so I think that proves that it is not the light itself. It seems like either the dimmer or the wiring. I am going to try to replace the one dimmer with a standard switch and see if the problem persists.
    – Chuck M
    Commented Sep 18, 2020 at 12:13
  • Seems like a very good trouble shooting step, @ChuckM. Fortunately, a simple toggle switch is only a couple of bucks, so it's not an expensive one, either.
    – FreeMan
    Commented Sep 18, 2020 at 15:49

2 Answers 2


So, I have this working now.

  • I tried a simple switch and it did not help
  • I swapped the lights and it didn't help

Finally I took down the two back lights and re-did the wiring. The non-working light was chained from the other light so I took the caps and re-wired everything I could. Once I put it back together it worked. So I can only assume that there was a shaky connection for one the connections. It is strange that it worked after a time after turning it on, but that does seem to be the issue.

Thanks for everyone's help.


I had the same. Two kitchen screw-in LED lights, in series, controlled from a single dimmer (LED compatible). One would come on immediately. The other would remain off until about 20 mins after. Then work, switch on/off and dim as expected. Replaced the dimmer. Swapped the lights (for LED and filament), re-seated the wires. Nothing. Then swapped the actual light fittings. The “good” one worked and the dodgy one remained off. So, the fitting was under suspicion. Checked with a voltmeter and all checked out. Saw the same voltage at both sets of bulb contacts. So… why was one bulb not lighting if it had the same voltage arriving at both bulbs? Logic only really pointed at the bulb/contact interface. Cleaned the contacts in the fittings with sand paper and… fixed. Why did dirty contacts result in a delay? I can only assume it was an almost imperceptible arcing across the contact that eventually broke down to allow a full connection. In short, same as OP. Dodgy contacts. Hopefully that helps someone.

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