I have a '98 A4 Quattro sedan. I unlocked the driver's door with the fob and pulled the car in the garage to change the oil. While I was warming the engine up I closed the driver's door. The door did not shut all the way, only to the first latch. The driver's door would not open even though the lock rod was up. All of the other doors were locked. I had to get my other key. The fob would not unlock any of the doors. I had to manually unlock the passenger door and open the driver's from the inside. I shut the driver's door. It still would not open from the outside even though the lock rod was up. I can lock and unlock all of the doors and set the factory alarm by turning the key in the driver's door. Sometimes the driver's door will open from the outside, sometimes it will not. I searched this forum and did not see any complaints that match. I have a shop manual but it is pretty vague on the actual operation of the locks other than they are vacuum operated. After looking at the wiring diagram, I am wondering if the driver's door contact switch is bad but I'm having a hard time finding the central locking module. The manual does not show a location. Any ideas?? I am a mechanic by trade so I would appreciate only intelligent replies. Please no "are the batteries good in the remote".

 

The central door lock pump is in the trunk on the right side burried under the trim carpeting

. It looks like this (note that mine was broken for this picture, you can see the shattered wheel)


My guess is that your pump is about to die. Mine acted like that for a while before it died. I got a new pump form a junk yard in denver for $2. The dealer will want $500 for a whole new module.