On Sun, 15 Jun 2008 10:14:36 -0400, John Smith
wrote:

I just bought a 3-way switch. I notice that when hot wire is connected
to the black screw, both traveler wires are always hot no matter how I
flip the switch (the hot wire coming out of the other 3-way switch is
always hot, not responding to the position of this switch).

I measured the voltage across the black and either of the two traveler
screws and it was 0. However, if I measure the resistance, it does seem
to work (0 between the black and one of the traveler screws and infinite
if the switch is flipped. Same for both traveler screws.)

This doesn't make sense, does it?

You didn't say if the switches ever worked.

If you just bought a new switch, the chances the new one is bad are
low.

It sounds like the wiring from the other switch may be the one that is
wrong.

If the switches were working properly before you "fixed" them, then
what I would do is take both switches off and locate the hot. (only
one of the 6 should be hot.

I would then put the new switch at that spot and check the other side.

Take your tester to the other point and see if the new switch makes
two of the wires hot by switching back and forth. The wire that
doesn't go hot should be the common.

Reminder: Always turn the power off before making any wiring changes.

A good 3 way will have 0 ohms between the common one traveler in one
position, and infinite ohms between the common to the other traveler.
When you flip the switch you should have the reverse.