Have a 2 way switch with 3 wires

[jayman13]

Thanks to this forum, it has been very helpful.  I recently began trying to change what I thought was a two-way switch in my den with a PLWO1-I.  When I took the original switch out of the switch box it has three wires attached to it.  I don't see any other switches that could be controlling this light.  Any ideas what I can do?  Can I still install PLWO1-I and just cap off one of the wires in the switch box?

[Brian H]

Did the original switch have an outlet or pilot light on it? If so the third, probably white, was neutral.
If one of them was green or bare copper and screwed to the metal mounting frame. It is a ground wire.

If it really is a three way and you don't know where the mate is. You maybe able to find the two out of three to make it work. In that case if someone actually found the mate and flipped it. The PLW01 would stop working. 

[jayman13]

None of the wires is a neutral wire as I can see the white neutral wires capped in the back of the box.  Nor is it a bear metal wire attached to ground.  Very odd.  So assuming no one can flip another switch to that light I should be able to use a 2-way switch here right?  I just have to figure out which one is the one that goes to the light and which one is the hot wire?  Just annoying because one of the wires is attached at the back where you have to stick a small metal pointy thing to try and pull the wire out...

[Mellowmark]

How many screws are on the switch? If it only has two it is most likely a single pole switch.  And the third wire is just another hot feeding down the line.