2003 bitsa mini cooper s, new to friend. bought with "just needs a recharge" oath. no other complaints. holds Vac for an hour, begin recharge. please take note i have two large fans running at ear level, i'm looking for compressor engagement, and it does engage. high side spikes crazy on first shot of second can. it is then i notice no fan running. shut it down, the car is at center temp on gauge, still no fan. ohm the low side open line, car side of the plug after cool down still gets 12v at start on low side, minutes later 12v on high fan pin. replaced fan assembly and repaired the high speed signal plug. fans now work as designed. start car cold, turn on ac, no fan, no ps fan. compressor is running., fan actuate commands for engine temp. no ac fan call, or no response. if the pressure sensor is calling for the compressor, why no fans?
i'm at the point of replacing the 80 dollar pressure sensor, knowing that isn't going to help but i don't want to put the ecm/relay panel/air box together without knowing which direction to go.
when the fans kick on, i get cold vent air and my number start looking sane, but returns as expected to crazy when engine temp dips to 100c and the coolant circuit shuts off

 

Both the fan and compressor are controlled by the DME. So if there's a problem you're most likely to track it down with a BMW/MINI specific scan tool.
Look for error codes and if there aren't any try to deduce what's going on from the live stream of sensor data and/or activating service functions.