Yes, check the motor <https://forums.tdiclub.com/index.php?threads/2010-jetta-door-latch-fix.451892/>. The OBD (on-board diagnostic) tells you. I had this issue 4 years ago with the pax door in a 2007 VW Rabbit. There are guides in the net how to get to the motor. There is even a description there that explains why the electromechanical buildup suffers from a design flaw: Since the motor can run back and forth, it has to stop at either end. There, it is stuck(!) and draws so-called short-circuit current that burns the brushes and the commutator. (Only in later designs a smart clutch makes the motor idle, thus making it draw only no-load current.) The entire inner surrounding is black of CuO (copper oxide), preventing the motor to run. If you open the motor and clean it inside, you may have peace for a while. Opening the motor is tricky - I've described this elsewhere. As a precaution a bought a stock of these motors Mabuchi FC-280PD-20150. They were made in a Saigon suburb and available from Brazil(!) only. So far I didn't need them.