There's one other possible source for extra water vapor in the cabin that I've had happen on a Saab. I noticed a similar situation, along with a slight coolant smell--turned out there was a small leak in the heater core! Once that was fixed the foggy windows and the odor both had vanished.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)