School me on 3 way switches. Magic.

Discussion in 'The Garage' started by dentedvw, Nov 18, 2012.

  1. dentedvw

    dentedvw Where did I put that

    Joined:
    Mar 18, 2008
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    2,175
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    Joking, I get it. Kind of. Well, the problem is that I have a pretty old house, and one of the three way switch circuits needed a new switch. Pretty simple, right? :rofl
    I pull it out, unscrew the wires, and put them on the new switch. Newer switches have one terminal that is darker than the others, and that's handy. But, this old thing didn't. So, I guessed. I guessed wrong.
    While I was at it, I went ahead and tried to replace the other. Really, pulled it off because it was the same vintage, mid sixties. Great time for old trucks, but bad time for electrical switches.
    No light was shed there. So, I pulled down one that was replaced this summer and does work, but wiring it as those were didn't help either.
    So, I pull out the multi meter, looking at the wiring diagram that comes on the package, thinking that some light will be shed (ha ha!) but I measure a bit over 50 volts. I measure it three times, and then think that I probably need more beer. :freaky
    I might try another meter.
    I am confused, maybe I am just burned out from a weekend of tearing out walls and framing and plumbing. :lol3
    Money that would have been better spent on a weekend trip, but this makes the wife happy.

    Anyone have some troubleshooting tips for me regarding three way switch circuits?
    #1
  2. dentedvw

    dentedvw Where did I put that

    Joined:
    Mar 18, 2008
    Oddometer:
    2,175
    Location:
    ☼SLC-ish☼
    I think it might be one of these because there is only the three wires in each box.

    [​IMG]

    [​IMG]

    One of the switches lights up, and it's lit, no matter which way the switch is switched. I think that means I am on the right track? :huh
    #2
  3. dentedvw

    dentedvw Where did I put that

    Joined:
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    It was the second one.
    Sometimes I just need to post something stupid to figure it out. :rofl
    #3
  4. RVDan

    RVDan Long timer

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    Do you feel like you're talking to yourself? 😄
    #4
  5. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    OK, so I guess you figured the problem out then? Good.

    For the sake of completeness, if anyone is trying to figure out how the heck these things work here is a pretty good diagram I just grabbed off the web:
    [​IMG]

    As you can see, it seems magical until you look at it and realize that it is just about as simple as you can get, then it makes sense.
    #5
  6. vwboomer

    vwboomer Buffoon

    Joined:
    Feb 12, 2008
    Oddometer:
    11,295
    Location:
    WI
    unfortunately there are 4 or 5 ways of wiring a 3 way switch. I ran into a problem in my attic. hall light feeds off same power as a couple other room lights. tapped into it for a bath vent then couldnt remember which wires were hooked up to what :scratch

    the power goes to the light first. i have new switches for the 3 way so its a matter of sitting down and looking at it. new installs arent so bad, but figuring out old wiring is always a blast
    #6
  7. the_gr8t_waldo

    the_gr8t_waldo Long timer

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    disconnect all SWITCHES, energize the curcuit and find the lead that's energized ALL THE TIME-once found turn off the power and.....connect this lead to the odd colored screw...then connect the remaining two leads to the remaining, common colored screws... turn on the power back on and.walk to the other switch location and find out what wire is energized at the second switch location. (lets call this lead "A") then go back to number one switch and flip it...go back to switch two location and find and mark the new, energized lead-(this we'll call "B")- turn off power and connect leads "A" & "B" to the two common colored screws on switch two- the last remaining wire at switch location two will go to the odd colored screw---renergize the cirsuit and test for full 3way function -
    #7
  8. concours

    concours WFO for 41 years

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    So, I have a three way light circuit... one switch is also equipped with a pilot light. The pilot is always on, controlled light does not work. Lamp failed? Switch? Before you say "just throw a new lamp in and see" understand the fixture is 25' up in a pine tree 100' from the house:rofl
    #8
  9. wolfhoundaddy

    wolfhoundaddy Been here awhile

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    prescott, arizona
    #9