In regards to your SUBJECT (albeit contradictory post), vacuum pump is in the trunk on the right side behind the cover. Seems as though you know this though!
Well per your request, I just tried to open my CDRom, 202 Systems Information, but the damn thing is scratched and will not read! I am having my mom bring home a Data Cd from the office, and I will try and copy it on the other computer (less sensitive reader) and then see if I can read it from there (that computer doesn't have a supported driver to read the cd though?).
I can't even be sure if it has the wiring diagram, as it's not a Tech manual/CD whatever, but it might be a start.
Also keep in mind that the W202 tech CD should be coming out in September, per Mercedes-Benz. That will be an IMMEDIATE purchase! For me, anyway.
Ok, that's all the help I can give for now. But since you are doing this yourself, I have a question. My aftermarket alarm/remote today began acting up. When I click the lock button, the alarms chirp, but the door locks do not activate. If I open the door, the alarm will set off as usual. So the alarm is activating but the door locks are not. Upon further investigation, I noticed that the switch on the console is fully functional (unlocks and locks doors properly). I also sat in the car, activated the alarm and then unactivated it. I was able to hear the vacuum pump turn on when I would disactivate, or UNLOCK (via remote) the car. So I know that the alarm is working normally to unlocking the doors, but there is no pump activation when LOCKING/activating the alarm. My question:
Are there 2 wires to the vacuum pump, one for unlocking, and one for locking? If so, then I am assuming the lock wire (wherever the alarm is put in-line with it) is acting up. Today it has worked and not worked, then worked, and now not worked. Sorry to distract from your original request, but I was just hoping you might be able to help! Thanks again, and I'll keep you posted. GOOD LUCK!!