W140 Central Locking
 

The central locking of my S500 1995 just stops working. I have read that the vacuum pump also helps the back headrests and the A/C flaps, but in my car these are working ok.
Is this correct? Or the pump operates only the locking system? I reached it under the rear seat but it is not making any noise. Fuse is ok.
Can be the pump that broke?

Try locking from the passenger door and trunk, might be the lock.

In the earlier body cars the pump is for the locks only (and orthopedic seats if equipped), I believe the W140 to be the same.