...but you know, some AC systems are charged from the High Side> I've seen documentation on it several places. Look on any Interdynamics Gauge Box or the Haynes AC manual. Intuitively, to me it sounds wrong. I mean the high side at 200 psi could blow out the can! But the reason I asked is Mercedes does evrything different than any other car I've worked on--fuse box in engine compartment, timing chain, I thought maybe this was another example of this...