The A/C vacuum control valve block is beneath the under dash panel on the passenger side.

Here is a link to the vacuum system http://www.peachparts.com/shopforum/showthread.php?t=89524

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator