if you have 3 wires at each switch location and you have determined that the black is common then the other 2 wires connect to the travelers. the common 'll be the dark screw

Right. Tried that, switch wont work properly.

Could it be that I have a faulty switch right out of the box?

It will turn on or off at either location, except if one switch is on already the other switch wont be able to turn it off. if you turn off that switch the other will then be able to control the light.
Does that sound like a faulty switch or faulty circuit?

Thanks again.

In addition to that when following the steps in the other post about trouble shooting a three way switch, i found out that with one switch out of the box completely ( no wires connected) and the power on the other three way switch could still control the light on and off.
The wiring worked before and it was a three way not a four way switch that was installed, and I changed nothing but the two switches. I also ran a continuity test and swap both three way switches to see if that was the problem - it was not.

I'm at a loss here as to how to proceed next.

Thanks again.

well then the 3 way thats attached is the one with the common feeding the light source

i would assume that the issue is that the 3 way on the other end has the wrong wire on that common

try putting the white wire on the common and the other 2 on the travelers

Nope. tired the white and tried the red. ? no change.

but thanks.

you have a 4 way switch(es) in between?

Not that I am aware of? The switches are at the top and bottom of the stairs and there isn't another switch near them anywhere. they are even in a single gang box. and there is only one light.

Just a quick follow up.
I got it working. Turns out when you have two hot wires in each box, you put both the hots on travelers not the common. (on their respective switches)
Thanks for the help.