Don't you guys ever wonder when the AC turns on. I mean, on all other cars, there is an AC button, but not on our Mercedes. So the question i think must have crossed everyone's mind is "When does the AC turn on?"

I seem to have a pretty good theory. The AC turn on when you set the climate to be lower then the outside temp reading. I've been keeping track of this for about a year and a half and this seems to be the solution.

Anyone who has another theory, please do share

I think most of the japanese air cond
got a temp sensor attach at the evaporator.
once the temp exceeded the set threshold,
the compressor will engage and the air cord is on.

Three conditions for the A/C to engage (at least on my 1982 300D, in theory...): outside temperature must be above 2 degrees C (34 F), there must be pressure in the A/C circuit (to prevent burning of the compressor) and the climate control brain asks for cool air.

Pushing in the EC button is the only way to prevent it from engaging.

Hope this answers your question.

Nicolas

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1982 300D - http://members.xoom.com/nicodore/