The good news is...I do not have a leak!
The system has refrigerant. I took the car to a mechanic friend who has gauges. A/C pressures are OK! However, he has NO MB experience.
The bad news is...I still do not have a working compressor.
It has to be a sensor/electrical i.e evaporator sensor. The book shows a fancy tool to test the PBC including the sensors (which I do not have).
Any other suggestions before I take the car to a MB pro?