I just replaced the switches on a 3 way light fixture and wired them exactly how they were from the wall before. When I turned the power back on everything worked fine and the 2 switches activated the ceiling lights as they were supposed to. About an hour or 2 goes by and now neither switch works and I haven't the slightest clue why. I went to the panel and cycled the circuit but it didn't help.

Anyone know what may be causing them to suddenly stop working.

They are brand new switches and one of the hot wires on one switch has some splitting of the protective cover but I taped it with electrical tape.

  • It was wired with the "backstab" configuration before. I cut the wires, stripped new sections and put them in the clamp down plates that screw down. Granted I could have one of those loose or improperly connected, but I'm at work and can't check now and couldn't check before leaving since other people in the house needed that circuit to get ready for work.
    – John N
    Apr 27, 2016 at 19:01
  • Thats a good question, but I'm wondering why it worked for a short time, then just seemed to stop
    – John N
    Apr 27, 2016 at 19:08
  • When I finished, each switch could independently toggle the lights regardless of the position of the other switch. It seemed like I did everything right which is why it is baffling me as to why it would suddenly stop working
    – John N
    Apr 27, 2016 at 19:13
  • 4
    Dumb question: did you check the bulb? Apr 27, 2016 at 19:20

2 Answers 2


I figured it out after opening it up. The old switches the previous owner installed were actually upside down and the common terminal was in the wrong spot, so when I tired them up the same way the hot was only being properly fed by one switch and when that switch was off the other switch wouldnt work. Once I figured out that that was the problem it was an easy fix.

  • Too bad no one suggested that. Oh, wait.... :P
    – isherwood
    Apr 28, 2016 at 21:27

Use screw colors, not position, to identify wires

After you change a few receptacles and plain switches, it's really easy to get used to the idea that the terminal screws have standard positions. They do not. Terminals are identified by screw color or labeling. Position has nothing to do with it.

The poster child for this fact is the 3-way switch. There are only 12 possible positions for the screws, yet due to the fact that these switches depend heavily on quantum mechanics, no two 3-way switches have their screws in the same place.

So you must go by color -- in the case of 3-way switches, the black screw is typicallt common.

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