Dear forum, the instructions for changing the actuator has helped me a lot more. In the meantime, I suspect that the motor is not defective (both the motor and the potentiometer seem to work to recognize the position). What I suspect, however, is that the air conditioning system has already brought the actuator into a protective position and therefore no longer drives it. In the manual, “base settings with the test system like Do I have the opportunity to get to it? Does a VCDS help me here? Best regards, Stefan