I've owned my 99 320 for about 2 months now and have yet to see/hear the compressor work correctly. Within about 2 days, the tanks will drain to 0 and the compressor never kicks on. It WILL turn on if I push one of the "up" buttons on the HWH leveling board. While the button is pushed (by someone else), I can pull the relief valve on the compressor and it releases air....