I assume you’re talking about a ‘93 sedan. Looking at the Service Manual, p. ELE-227 describes the Power Door Locks for 1993. There, you’ll find the Central Locking Module (also known as ZVM). Pin 9 from the ZVM goes to Pin 9 on the Comfort Relay with a violet/yellow wire (p. ELE-233). Pin 8 on the Comfort Relay is ground, with a brown wire.

I’m assuming the ZVM is some sort of computer; thus, the Service Manual doesn’t list schematics or behavior of Pin 9. However, Pin 9 on the Comfort Relay (the input from the ZVM) goes to a transistor, which then controls the relay itself. Thus, I would guess that Pin 9 should be high when a door is closed, and low when a door is open. Of course, Germans being Germans, who knows? In any case, if the voltage on Pin 9 does not change when you open or close the door, then the ZVM is probably doing something funny.

Update: Of course, that would be the behavior once the car has been turned off — the windows will continue to operate until one of the doors is opened. When the car is actually turned on or running, I would expect Pin 9 to be high regardless of the doors, since the windows are supposed to operate any time the car is on/running.