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Discussion Starter · #1 · (Edited)
First post and I'm a semi-beginner (the most dangerous kind, I know) . . . I've replaced several outlets, switches, and fans over the years. Nothing else.

I am replacing an old 3 way switch. It had a crack in the rocker, so you had to push to turn it on. Other than that they worked fine.

Today I replaced it, it's an old house so the wiring is old. I took note of where the wires were in the old switch, and I made sure the new one lined up correctly. There are two black wires, they go around the two brass screws. There is one white wire, it goes around the one black screw. (no ground wire)

This new switch only works when the other switch is in the up position. When the other switch is in the down position, the new one doesn't work at all.

I thought the fact that it was a lighted switch had something to do with it, so I just tried it with a regular switch. Same problem.

Am I missing something here? I'm sure I am, please fill me in.

Thanks!
 

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are the three (red, black, white) the only wires in the switch box? Do you have a voltage probe?

Most likely barring device failure or screws misinstalled), your wires are simply on the wrong terminals. I have no explanation why this would be, given your careful attention to details.

If you have no ability to identify voltage, I believe there is little risk to trial-and error with these three wires, but would prefer confirmation from another before proceding.

If you have the ability to identify voltage....remove power on the circuit. remove the three wires from the switch and leave loose without any contacting any other. Reapply power. Identify the wire with voltage. This is one traveler. Change switch (other one still installed) position. Idenitfy wire with voltage. This is your other traveler. These two travelers go on the brass screws. The remaining wire goes on black.
 

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Discussion Starter · #3 ·
Is a voltage probe the same as a circuit tester? It's two probes, a red and black. There is a light that lights up when it detects electricity. It's been years since I used it.

Can I use this? Just touch one of them to the wire, right? Or is it both?
 

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Yes you can use the voltage probe. Voltage is always measured between two points or two spots, thus the two leads red and black. First test the probe light by inserting the leads into the two slots of an outlet (receptacle).

Which 3 way switch gets the power? Connect the probe leads one to the common screw of the switch and the other to ground. For one switch the power will be on all the time regardless of the positions of both switches.
 

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They are not the same. If you can find a source of electrical ground, you can use your voltmeter, but you state that there is no ground. Perhaps you have a metal box and it is grounded? If so, one probe on the box, and the other on a wire. Set the meter for a range of 200 or so volts and use AC setting.

Given your description including a ligt, perhaps it includes a voltage probe as well. I am not familiar with such a feature on a voltmeter.
 

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Discussion Starter · #6 ·
Thanks to everyone for the advice. I should've been clearer...this is very old wiring. I mean the wires have the cloth stuff wrapped around the wires. One of the boxes had a red wire but it was wrapped off before i moved in.

I figured it out, on of the two 3 ways needed to have one the wires switched around. It turns out that lighted switch was a good indication of when and where the power was making its way to the right place.

Thanks all! Look forward to hanging around more!
 

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Screw position is not same between switches. You have the wrong wire on the common terminal(black screw). The good thing is it will only take a maximum of two more tries before you get it correct. Put a different wire on the black screw. Try it. The other two screws don't matter.
 

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Discussion Starter · #8 ·
Screw position is not same between switches. You have the wrong wire on the common terminal(black screw). The good thing is it will only take a maximum of two more tries before you get it correct. Put a different wire on the black screw. Try it. The other two screws don't matter.
I know . . . did you read my last post? I got it. Thanks.
 

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First post and I'm a semi-beginner (the most dangerous kind, I know) . . . I've replaced several outlets, switches, and fans over the years. Nothing else.

I am replacing an old 3 way switch. It had a crack in the rocker, so you had to push to turn it on. Other than that they worked fine.

Today I replaced it, it's an old house so the wiring is old. I took note of where the wires were in the old switch, and I made sure the new one lined up correctly. There are two black wires, they go around the two brass screws. There is one white wire, it goes around the one black screw. (no ground wire)

This new switch only works when the other switch is in the up position. When the other switch is in the down position, the new one doesn't work at all.

I thought the fact that it was a lighted switch had something to do with it, so I just tried it with a regular switch. Same problem.

Am I missing something here? I'm sure I am, please fill me in.

Thanks!
If the switch only works while one is up it means you put the common under the wrong side on the 3-way switch. the common is generally painted black on the switch.
 
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