Now that the close assist is working on this car, I have to figure out why the AC cannot be turned off for the rear seat passengers. It blows cold air (today was 75 degrees and the vent facing the back seats on the center console was blowing at 58 degrees while the front ECC was set at 70 degrees). This car does not have a dedicated rear climate control system, it just directs cold air from the front AC system. What is involved? A monovalve? Vacuum door flap stuck open? I can't find any TSBs on this problem either.

That's just the way it works, if you don't have the rear climate control option. You can only close off the vent at the vent itself. If the wheel that is supposed to close the vent isn't doing its job, it is possible that the cable operating the flap is out of its seat and needs to be reseated. Heat is delivered only from under the front seats.

The W140's with rear climate control are similar in that only air conditioned air is delivered to the rear system, but to get heat, the rear climate control then routes the cooled air through a set of heater cores dedicated to the rear system to re-heat the cold air. Funny, eh, but I guess that was the easiest way to design it instead of building in a whole second air intake for the rear heater.

Brett

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1997 S600 sedan