Hey all. I"ve got an 89 740t, which was converted to R134a 3 years ago. The system has held freon for these years with no leaks but it seems to not be activating as of late. I checked the 12v wires going to the compressor and jumped the wires coming from the dryer. I can get the a/c compressor to activate if the car is revving near 3000rpms, but anything lower, and the a/c is dead. Also, the compressor makes a loud scratching noise when the clutch seems to engage, and as said, will not engage unless the engine is revving at higher rpms. Could it be my compressor? My clutch?