Where is the ac drain for a passat vw?

You need to access it from inside the car. It is easiest if you remove the glove box - 4 Torx 15 screws and unplug the light. Then pull the carpeting and pad back as much as possible from up under the dash. The drain is on the upper left of of the foot-well on the passenger side. To clear it you will need to pull it apart and either stick something long and thin through it, or blow compressed air through it. You cannot get to it from underneath the car as you can with almost every other car. The drain comes out by the catalytic converter behind the heat shield. It is neither visible nor accessible.