Solid advise by cdplayer.
Don't think the standard '85's had a fuel door actuator nor a lumbar support so you probably won't have to worry about those.
If you hear the pump running, I'd suspect a vacuum leak. Remove the rear seat as advised (can be harder than one would think). Start following the vacuum lines which will require pulling up some of the floor carpet. Find the places where it splits off going to each door. Disconnect to isolate each door and hook that line up to your mightyvac to determine if that door is working correctly before pulling the door panels off as those are a pain and the plastic anchors on the back tend to come off when messed with (hot glue reattaches). Hopefully you will find the leak in the lines feeding to the doors.
Although this is for the W124 body, I think most of these system cross over to the W201 (190D)
80 Central Locking System
Good luck.