Asked on Sep 11, 2013

Frustration with Three-Way Light Switch

John @ AZ DIY GuyLandlightSMighty Mo Electric
+5

Answered

After 10 years a three-way light switch stopped working. I replaced both switches, but I must have missed something because the switch only operates 'sometimes.' We have to put switch A in the up position so that Switch B will work. Did I invert the switch leg? I attached the new switches using the exact same order as the old -- which had worked flawlessly for years. Therefore, I'm wondering if something else is at fault (no pun intended).
7 answers
  • You are not alone in this situation. It is most likely the way it is wired~sorry to say...it happened to us and my hubby and I had to work through it. There are some great sources for 3 way lighting on the internet and we have googled them and used them. Also did you check out the light? You know lighting can go "bad". Take the light down and check the wiring and check for any burnt or loose wiring (after you turnoff the breaker)

    • Joel Williams
      Joel Williams
      on Sep 11, 2013

      @The Garden Frog with C Renee Agree on the incorrect wiring, completely. However, regarding the light fixture, it operates "sometimes," so I don't imagine that my problems are related to the light itself, but rather the switch wiring. Thanks for the suggestion.

  • As far as I can see from the pix you should have 2 white wires together in the box. The odd black wire would go on the odd dark colored screw on the switch. The red and black wires from the same cable go on the other screws on the switch. Doesn't matter which screws. That would be at both switches. That's about as close as I can get from the pix and without testing.

  • Arkadiy Svist Electrical
    Arkadiy Svist Electrical
    on Sep 12, 2013

    As I can see, there are 2 black wires and one red. So, there are two different cables. Connect black wire from cable WITHOUT red one to black screw in 3-way switch, another black and red wires to other screws. Repeat for second switch if necessary.

  • HandCraft Solutions
    HandCraft Solutions
    on Sep 12, 2013

    The best way to repair a three way circuit is to understand how it works. You have obviously three wires on each switch. Each switch has a black or darker screw than the other two. This is the screw that either the line wire (main feed wire that powers the circuit) or the load wire (wire that goes to the light) is attached to. The other to screws on each switch are what are known as traveler screws. These screws will be connected to the two wires that travel directly to the other switch. These two wires will be connected to the traveler screws on the opposite switch. To correctly identify all wires, disconnect all wires from both switches. There will only be one live wire. This wire should be connected to the dark screw on the three way switch. The remaining two wires at this switch location should be attached to the two remaining traveler screws. At the second location, find the cable that has the black and red wires coming from it. These wires will be the travelers from the other switch. Connect these wires to the traveler screws on the this switch. The remaining wire will be the wire going to the light fixture. As long as you only have two switches in your circuit you should be back in business. If more than two switches are in the circuit, another configuration will be necessary and further instruction will be necessary. I really hope this helps. God bless.

  • Mighty Mo Electric
    Mighty Mo Electric
    on Sep 13, 2013

    One screw is a different color than the other two, typically it's bronze or black, while the others are silver. The black.bronze screw is called 'common' the silver screws are called 'travelers'. Where power enters the circuit at the first switch (hopefully, if you have power to the light first, this is harder to explain), that wire must go to the common screw. The other two wires go to the travelers. On the second switch the hot wire that goes to the light must attach to the common. Quickest troubleshooting method, if you have one of these $3 voltage tickers that lights up when held to the hot wire, is to unscrew all the wires, figure out which one is hot, and attach that to common then work from there. On the second switch if you don't know which wire goes to the light, you're going to have to guess and test until the get the right one. But everything gets easier once you get the first switch wired properly. Good luck!

  • LandlightS
    LandlightS
    on Oct 2, 2013

    Maybe this link will help. Take your time and read thoroughly and you should be able to understand three way wiring. http://www.homeimprovementweb.com/information/how-to/three-way-switch.htm I hope this helps. Gary

  • John @ AZ DIY Guy
    John @ AZ DIY Guy
    on Feb 13, 2014

    Electricity is blind. Although there should be some logic in how they installed the wiring originally, it's entirely possible that the colors of your wires have no bearing on their function. That can really mess with your head. I recommend you spend some time figuring out what goes where first and identifying the individual wires. With that done the wiring steps you can find on the net, will make more sense.

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