Hello, my w201 suddenly stoped locking doors, at first the rear drivers door started locking strange, some times it locked some not, then all the locking system is down, nothing happens

I've searched on manuals and all over internet and there is supposed to be a vacuum pump below the rear seat, so I went there, BUT THERE IS NO PUMP, there is nothing, no cables, no vacuum lines, no pump, nothing.

Maybe I'm searching for something that does not exists in my model, any ideas?
Thank you.