And yet another 3-way question

Seems like this 3-way light switch thing is either all-the-rage or more complicated than folks think! Everyone elses problem seems a bit more complicated than mine may be.

As the 3rd or 4th of my numerous honeydo tasks , my wife requested that I replace all the toggle switches throughout the house. No major deal -- got the whole thing done in about a day, not bad for a novice. But, I think I mis-wired the 2 3-way switches.

Before I started messin' with them, either switch would toggle the connected light on or off, as expected. After replacing them, they light only comes on at certain combined switch positions.

The first set of switches lie at the top and bottom of the stairwell leading from the main level to the top floor of the house. Here's what happens with each switch position:

Downstairs switch up,
Upstairs switch up,
Light ON

Downstairs switch up,
Upstairs switch down,
Light OFF

Downstairs switch down,
Upstairs switch up,
Light OFF

Downstairs switch down,
Upstairs switch down,
Light OFF


The second set of switches lie at the top and bottom of the stairwell leading from the main level to the basement of the house. Here's what happens with THESE switch positions:

Downstairs switch down,
Upstairs switch up,
Light ON

Downstairs switch up,
Upstairs switch down,
Light OFF

Downstairs switch up,
Upstairs switch up,
Light OFF

Downstairs switch down,
Upstairs switch down,
Light OFF


Any idea what I may have done wrong?

-Joe

 

Joe as a guess I think the switch at the top on the first one may be wired wrong and the switch at the bottom of the second. Understand these are guesses but it may be possible to sort out the problem this way. On 3 way switches there is one terminal that is colored different than the other two. This is normally where the black conductor is wired. Might check this out first. It doesn't make any difference on which terminal the other two (carriers) are wired.

 

This one is easy. You misidentified the "common" on one or both switches of each pair. It's easy to do if you don't pay attention, or if you switch brands of switches and assume that screw position means something.

At this point, it will be easiest to repair by trial and error. There are three wires and three screws at each switch. It will take at most nine trials for each pair to get it right. Make a chart for yourself so you don't end up trying the same combination more than once.