Geez Larry, that 100 words per minute paid off here.. while I was trying to word my post a little more gently, due to self imposed political views which encourage female mechanicing... I have to say that you are correct again .
Jassz, Please listen to Larry. You will be much better off.
And really consider buying the Mercedes Factory Shop manual on Air Conditioning and Climate control for your car... a wonderful procedure guide and money saver in the long and short run.