3 way switch help please!!!

[bigjcw1023]

I have a 3 way switch setpup at each landing for my basement stairs. I replaced the three way switch at the top, and it is a combo switch. Single pole/3 way. tWO LITE TERMINALS AND A COMMON. i WIRED THE TWO WHITE WIRES TO THE LITETERMINALS AND THE BLACK TO COMMON. aLWAYS ON SITUATION DEVELOPED. tRIED SWITCHING ONE WHITE FOR BLACK AND DEVELOPED A SITUATION WHERE THE LIGHT TURNS ON AND OFFFROM THE NEW SWITCH, NOTHING ON OTHER SWITCH. tHE OTHER SWITCH IS TWO SEPERATE CIRCUITS, AND A SINGLE POLE/ 3WAY AS UPSTAIRS. tHE upstairs single pole controls the outside light and works fine. I have tried the two white and one black in all configs poss on the 3 way part of the switch. The two single pole wires are wired as beofore. PLEASE HELP

[RBM]

The colors don't mean anything regarding placement on a switch. On the old combination switch, was the bridge removed between the terminals of the common terminals? If so, remove it on this switch

[Terry]

Take a tester.

You will have one of the two situations.

One wire will be hot no matter what you do with the other 3-way

The other possibility will be that one wire will never be hot no matter what you do with the other 3-way.

The wire you identify like this will go to the dark colored screw.