Well Steve, they do good work believe it or not. And I don't have to pay $100/hr for them to come to the same conclusion that MB did. I just checked it again, now the compressor doesn't engage. Could that be due to low (or no) refrigerant or is there are fuse blown? FYI - the thing I call a sight glass is locared in front of the w/w reservoir in front of a box that has ASR (traction control?) lettered on it. And it did have bubbles in it a few weeks ago!