LT focus, recycle flap/motor.

[Rs31markie]

Hi all, I've just put a cabin filter in my focus, it had never had one. Whilst doing this I noticed that the recycle flap motor has been disconnected and the flap has been jammed closed. The motor is working but, it rotates too far, ie goes more than one complete turn. Does anyone know what controls this? Heater/ac ecu or something like that?
Anyone have any ideas? Worst case is I can just leave it on recycle.
Thanks mark