Recirculation flap actuator 348/355

Does anyone know, definitively, how the cabin air recirculation flap actuator is supposed operate on a 348/355? I posted about this a little while ago under the 348/355 section but got some (not all) inaccurate information

Specifically, I would like to know what, if anything, stops the power to the actuator when the flap reaches the fully open or fully closed position. What I have found on my 355 is that the voltage (12 volts) to the actuator never goes off when the engine is running. The only thing that ever happens is the voltage to the actuator reverses polarity when the recirculation button is pushed.

There are no limit switches to cut off power at the end of travel of the flap. There is no built-in timer in the ECU to turn off voltage after "x" number of seconds. There is no current measuring device that detects the increased current of the stalled motor, when the flap reaches full open or closed, to turn off juice.

Anyway, these are my findings on my 355. I'm interested to know if this is normal operation or if I may have a problem with my climate control ECU which allows voltage to stay on. Don't want to strip another gear train on my new actuator!