Hi Folks, I am a new member can anybody help please. First Mercedes 1999 C250 TD, very pleased with it. Problem with air conditioning. Been back under guarantee for few minor problems but air conditioning not working, system has been charged, dye and pressure tested and not showing any leaks, got fed up with keep going back and getting nowhere. No visible flow in sight glass so suspect compressor or clutch but Haynes Manual useless. Any way of checking clutch please. Thanks for any information.