Like I said, start off by charging through both high/low sides with the system off; this will build the needed pressure to trip the low pressure switch and enable the compressor to start. Again, once you decide you're going to start it, make sure to close the high side valve.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280