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Three way switches

There are two lights in the house we bought three years ago that don't work right. Both are on 3-way switches, and in each case, one switch must be "on," and then the other works the light.

I understand how 3-way switches work, and I can wire new ones, but I cannot figure out how these two are miswired!

Do I have to disconnect everything and then use a meter with extremely long leads?

Thank you,

Tom Barbour

Re: Three way switches

Find the switch that has power on one wire in all cases, that is the power lead that should be on the common screw of that switch. The other two wires will be switched one hot in the up position the other hot in the down position These are the travelers to the other switch. Check the other switch for the two travelers turning on and off with switch one. The remaining wire would then be connected to the common of switch two.

Unless you have the California 3-way wiring.

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