My C4 is at
http://www.hobbystage.net/porsche/whatever
We picked it up at the factory last May, drove 1600 miles in 10 days, 7 countries, tour of the castles of europe. When I returned it to the factory I told them that something about the A/C wasn't right, I had to keep resetting the "target" temperature in order for us to be comfortable.
We picked it up at POE in late June and that night, late evening really, in Alabama the outside of the windshield misted over fairly quickly. Having had some experience with this due to the totally idiotic design of Lexus's climate control I checked immediately and discovered that a substantial level of the A/C cooling airflow was being directed toward the interior surface of the windshield.
I over-rode the "auto" mode of the system and had no more problems with it all the way home to Seattle. I though it might be a failure of some manner in the car but when I got home I checked a 99 996 and it does the same thing.
Does anyone know why Porsche/Bosch does this?
My local dealer's service manager wouldn't even write it up as a customer complaint since he said it was a designed in "feature".
A desgn FEATURE.
More like a design FLAW !!!
The reason I had to keep fiddling with the setpoint in europe was because much of the cooling efficiency of the system was being used, and lost, keeping the interior of the windshield COOL in the hot sun.
And of course on a hot and humid day in Alabama when the temperature starts to fall in the evening the cool windshield will soon reach the dewpoint of the outside atmosphere.
This IS NOT ROCKET SCIENCE !!
So if you live in the south where it is oftentimes hot and humid in the daytime be very careful in your 996 about keeping that cooling airflow away from the windshield.
On the Oregon coast in the early evening I have had a Chrysler T&C windshield fog completely over virtually instantaneously due to the operation of the A/C within the vehicle inadvertantly cooling the interior glass surfaces. As we "dipped" down into a valley near the ocean shore the atmosphere was likely on the verge, cusp, of fog formation and guess what?