On a 1993 Passat GLX when the fuse is in place the air pump runs continually even if the doors are unlocked is this normal If not do all of the locks work off of the same air system?
If the pump never shuts off there may be an air leak in the system, or maybe a sensor could be bad or disconnected. I don't really know if locking system uses pressure or vacuum (I think vacuum). All the locks (doors, trunk, gas tank filler door) use this pneumatic system. On the models I have owned it has been reliable.