2000 Chrysler Cirrus Blender door?

Air Conditioning problem
2000 Chrysler Cirrus Front Wheel Drive Automatic 90000 miles

the little plastice piece within the duct work that controls the what the dealer calls the blender door broke. It is hooked up to the temp control by a cable and moves a door back & forth depending on how cool or hot you want it. At least that's how I under stand it from the Dealer. They will not sell the part by itself, they want to sell you the entire duct work assemble at a cost of $546. Is it possible to find just that piece- what is it called?
Thank you
Ron