Brendan McEvoy

Hi all, new to the site. I have a 52 plate 4.7 overland with a few problems which I am in the process of sorting, one of which is the blend doors, but there is a loud creaking noise coming from the heater area after the ignition is turned off. It can't be the blend door motor cycling as I have unplugged it locking the only working blend door into position.
It's very loud and can be heard form outside the car. Is there a flap that closes on the heater after turning off the ignition? It doesn't sound too healthy. It makes the noise a few times before it stops as though something is being forced past a tight spot. Would obviously like to get to the bottom of it as I am sure something will break eventually or overload the motor that is driving it.
Thanks in anticipation.
Mac