If your air conditioning has stopped working the chances are you have lost most or all or your system refrigerant. The fastest way of finding out is to attempt to have the system refilled by a specialist. They will evacuate any remaining gases and then pressure test the system before refilling. When mine was pressure tested it was immediately obvious that there was a leak somewhere within the condenser matrix situated in front of the engine radiator.

Download BMW 5 Series (E34) Condenser Change 1995 540i manual RHD PDF