Re: Possible Solution
We had VW Passat with a faulty door microswitch. Caused the doors to security-lock themselves every few minutes – when you press the button on the fob, the doors lock; a little while later, security locks engage so you cannot pull up the locking buttons inside. The faulty switch belonged to that security lock in one door. The security-lock was stealthy enough to engage to not immediately noticeable.
The most noticeable effect was that the battery was flat all the time. Car was in manufacturer garage multiple times for THAT. They couldn't find the fault – BECAUSE THEY NEVER LOCKED THE CAR inside the garage after hooking up the meters.
End result was disabling the remote and central locking (we had to unlock the tank door from within the boot when filling up), re-engaging the remote when selling, and not telling the buyer about it. Because taking the door apart to reach that switch would either be a bitch, or bloody expensive.