Two light fixtures in bathroom with 3 bulbs each. They can can 100 watt incandescent, I have 800 lumen LED, and there is a dimmer switch. In both fixtures, going left to right, the first two bulbs light and the 3rd does not.

  • I would check to see if the center conductor is not touching the lamp. turn power off and pull the small conductor usually brass up and try again. The center conductor getting smashed down is very common.
    – Ed Beal
    Commented Mar 17, 2016 at 18:52
  • 1
    Try moving the bulbs around; does the failure stick with the sockets or the bulbs? Commented Mar 17, 2016 at 19:35

1 Answer 1


If all 3 incandescents worked previously without issue (so you thought), then I'd have to say that the dimmer is limiting the current. LED's are very sensitive & require very tight limits to operate. Meaning, the first 2 bulbs are reducing the voltage & amperage to leave the third bulb unable to activate.

Your 3rd incandescent may have been dimmer than the other 2 or all 3 may have stepped down equally. Which leads to, put an incandescent in the 3rd sockets & see if it lights, it should. Then, try incandescent & LED combo's to see what does & doesn't happen.

You may be able to adjust the dimmer, very few have this ability & you'll need the dimmer's manual to do it. But, I'd replace the dimmer with a regular switch to confirm that the dimmer is the problem. If so, then get a new dimmer or keep getting them until one works. I say that because I doubt there's anything on the box to indicate any difference from 1 dimmer to another.

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