Morning all. Strange thing started a few days ago on the B Class. When you switch the aircon on by the button it starts up with a rattle but of when running. When you switch off via the aircon button but the blower is still on it will start rattling again after 5 min. You have to switch the blower off to stop it rattling and if you switch it back on without the aircon button being pressed all works great. No rattles. Is it the compressor on the way out or something else. As mentioned the blower without AC works fine. It's only on start up and shutdown of AC.