I have the same issue - I think my problem is the actuator that controls the Recirc damper. Do you also notice you can never get air to stop coming through the vents even when the fan is OFF? Also when your A/C is on, and the air is coming out of the dash and you push the ReCirc button, can you hear the door close, and the ac blow stronger?
Mine does not change, I think whats happening is its pulling in the hot air from outside b/c that door never closes. If you open your glovebox.. empty it all out, and hold the tabs you can get it to flop ALL the way open, behind there you can see the door.. when you push the recirc button it should open / close. I see mine does not...
Maybe I'm wrong, but I think thats my problem