AC Compressor didn't kick in on the old gal

It was a georgeous Sunday in the Nation's Capital and its suburbs where we live in Croom, Md. I think the temps got up there. I decided to drive down and when I turned the knob to blue with the fan on high and pressed the arrow button nothing but hot air. I didn't hear the compressor click in. So I went back to peachparts.com forums and found that there is a safety switch which prevents the compressor to kick in if it detects a low level of refregrent. I have a call in to Steve Rigoli (BTW if you are in the DC area he is a person to talk to for all your german car questions). Will see Steve on Tuesday and hopefully it is not the compressor this time. Talk soon!