http://mercedesdismantlers.com/diesel_vacuum_system.html
try this link.they talk about diesels but you may find something to help.i wouldn't think there would be too many lines UNDER hood for climate control and it shouldn't matter-gas or diesel

__________________
'95 s500 (bought for wife but can't bear to share!!!) 125kms
'92 legend 180kms
'88 tbirdturbo(fantastic car-only regular maint.)120kms
'87 mustang gt(gone)
'86 tbirdturbo(gone)
'85 mustang gt(gone-but not forgotten)