Light switches

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gcotterl wrote:

try here for a diagram that may help you
http://www.electrical-online.com/4-wayswitch.htm
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On Fri, 6 Nov 2009 07:35:03 -0800 (PST), gcotterl

Yo're going to have to write everything down and figure it out like a puzzle in the Sunday magazine or a game book. Make a drawing, assign a label to each wire. Keep it as a permanent drawing in your file for house repairs.
IIUC an electrician will have to do the same thing and will be only 2 or 3 times as fast as you are, while charging a lot for his time.
Acquaint yourself fully with the way 2 3-way and one 4 way swtich systems work, but bear in mind that the 4-way in your case isn't necessarily at the intersection, though it might be. Then acqquaint yourself with other ways of connecting the lightbulb, not necessarily at the end of three switches but in the middle possibly too, or before all the switches. That's something I can't keep in my head myself, but I've seen diagrams.
It may be best at some point to unscrew the lightbulb that is controoled by all these switches to keep return voltages from confusing you.
If you haven't changed any switches since this all worked, the one switch or two is broken, but they are of the right kind. Check how many wires is coming out of each. If you're lucky, that will firmly establish which is the 4-way switch, but maybe not.
Measure the voltage at each wire. The voltage between that wire and every other wire int he box and the voltage between each wire and ground. Then flip the switch and measure again. Later you may want to disconnect wires from the switch or from other switches to keep from being confused by
By using an external wire that reaches from one switch to the other, preferably with alligator clip jumpers on each end. first measure the voltage between wires at different switches. In those cases where the voltage is zero (analog meter) measure resistance. You're looking to find which wire comes out where. The color of the wires should help you find the other end of each wire, but sometimes they paint a black wire white, etc. Always measure voltage before trying to measure resistance.
It will be a fascinating puzzle, but if you make enough measuremennt and apply logic for long enough you should be able to fighure out which wire is hot, which is the neutral, whiche wires are travelers to the second (logical) switch, and which are travelers from the second switch to the the third, and which go to the light. But don't forget that the second set of wires from the emiddle switch or the first switch could got to the light and not be travelers at all.
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Bottom line is that if the wiring wasn't documented when the previous switch replacement was attempted, you are probably going to have to do it by trial and error. Lots of them! An electrician with proper meters could probably figure out with a few tries, but doing it without them will take time. Check out the diagrams for such an arrangement. It might seem obvious that the 4-way is the one in the middle of your arrangement but that doesn't have to be the case. Jot down what wires you have in each box, and you may also need to pull the lights to check them as well. If there a 2 conductor wires in a couple of the boxes, you can probably figure one of these is the supply, the other perhaps the load (lights). With all the wires safely separated, try turning on the power and testing for your hot. Then using a meter try to identify each line. Finally you can figure out what the switch configuration needs to be.
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Mark wrote:

In some older houses that is not the case, I have seen 3-ways where there's a 3-wire switch leg from the ceiling box to each switch box. Makes for a rat's nest in the ceiling box... (found this in the dining room of the same old house that had the miswired 3-ways in the stairwell)
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