I never use the OFF function. I use the AUTOMATIC function in summer when I want the AC to run and I use the ECONOMY mode when heat or unheated fresh air in desired. Even with the top down, I like fresh air from the floor and dash vents and of course on those cool days I like it warmed. I've read posts from other owners who've said simply that MB designed this system for a luxury car: "just set it at AUTOMATIC 70 degrees and never touch it again". But I can't think of any circumstances to ever switch it OFF.

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Resistance is Futile.