Recirculation Door Actuator problem
 

I'm working on a 2006 Charger. There was a loud clicking noise behind the dash which I have tracked down to the Recirculation Door Activator. All posts I have read seem to indicate either broken doors or malfunctioning actuators. This at first glance is neither. I can see the actuator opening and closing the recirculation door. I opened the actuator and can see no missing teeth or anything else wrong. However when the door reaches either the fully open or fully closed position the actuator continues to try and push it for several pulses. How does the system know when the actuator has reached open or closed? Is it some kind of feedback through the driver circuit?
I tried recalibrating but am I believe getting a DTC of 56-BLEND DOOR LINKAGE BROKEN which it obviously does not appear to be.

I realized that all three actuators are identical so swapped the Recirculation Door actuator with one from the driver's side and found that the problem follows the actuator. A new one is on order.