With any other car I've owned, Honda or Toyota, I simply hit the a/c button which turns on the compressor, then slide the temp control to wherever I want it. On the Mercedes, if I hit the a/c button (the stupid buttons with arrows on that are confusing to any normal person) I simply get cold air unless I put the temp wheel at a pretty hot temp, then it goes out the floor vents, not the dash vents. I was just wondering at what temp that it switches from dash to floor vent. Using the a/c button will control the fog but the a/c sucks a lot of power/speed from the 5 cylinder diesel.

Thanks for the FYI on the problem with the anti-fog stuff you used. I'll be careful. Using Rain-X on the outside is awesome; great stuff.

By the way, simply CLEANING the inside of your windshield with Windex or other generic cleaner really helps reduce fogging on the inside during warmer times of year. It can't prevent the normal fogging from warm inside to cold outside on a rainy day however, but it certainly helps a LOT during other times of year. Clean the inside of your windshield!

1991 300d, 95k