Central Control Flap Position - possible problem with the control motor

[BFeller]

I have a question about the central control flap. After suffering the usual problem with the foam falling off the blend door that problem was repaired. The cooling system was bled using an Uview AirLift. However, the system was still not generating a lot of heat. It is blowing cold air. I did some additional troubleshooting and and noticed the In Dash Temperature sensor was dirty. It is not clean, but does make a loud buzzing sound. A replacement is on the way. Digging deeper into the system and checking the flaps for proper movement led me to checking the Central Control flap.

Currently it does not seem possible to adjust any of the buttons on the AC control unit to make that flap close completely. When is does try to close, it sounds like the motor is trying to close it off, it moves, stops and the motor continues to whir. Dropping the blower motor and removing the passenger side vents and ducting have provided a good view. I can move it manually to completely closed, so nothing appears to jamming the flap.

My questions are: That flap should close completely? Would a failed In Dash Temperature effect the amount that the flap closes? Lastly, I can see the motor and put a hand on it - does anyone know if it could be replaced without dropping the Heater Air Box?