Posted By:
DaveI'm a little late to this post, so I won't actually give much of an answer. I actually am an electrical engineer, but that doesn't mean I've ever been taught in any school about things like house wires.
Having said that, I can always figure out what each switch is doing in house walls. Single, two-way, N-way, each has its details, but they're not hard.
Follow advice given here. If it ever worked right, the right switches were there. Try to find the bad switch (that's not always easy), and replace it with one just like it.
You have to beware of the insulation colors on these switches; often they are different from the wires in your house where they get connected. So, beware realy doesn't help, but before you take out the old one, write down the house wire colors and the switch colors, and match that.