My opposed automatic damper recently failed. I went out bought a new damper, wired the red to red, white to white, and have a blue left over. When calling for A/c the damper closes when off it stays open. I don't know if I bought the wrong damper, or if there is something a can do with the wiring. Please help

I have no idea how the original setup worked to start with. You might have had a old setup that was powered both open and closed and that would explain the three wire. Usually damper when replaced are done like same so there would have been no mystery if you would have bought a 3 wire to start with.