If there is a water leak into the car, it will cause this, putting the A/C on just dehumidifies the air.

If it is really cold outside and a warm body gets behind the steering wheel it will cause a slight fogging, but if there is water getting in the car evrytime it rains it gets worse, all the windows start to fog, and when you run the A/C it pulls the moisture out of the car, but as soon as you turn off the air, the windows will begin to fog again.

This freind of mine hasthis problem with an 07, my 07 just stays in the garage when its raining, I hate to get it dirty, and I have an old cherokee 2 dr for rain and snow days.

What you should do is take the car to a glass shop they can test around the windshield and the rear window to see if its leaking there, the windshield is the biggest problem with water leaks, they use comprssed air and work around the glass and when it hits a void it sounds different, or just have the glass resealed, it better than watching the car eventuly rest away from the inside.

 

i didn't read too many people's replies, but i'd suggest just cleaning the interior's glass... i forgot what it was called, but the new car smell is vapor or something from the plastics in the car. and that sticks to the window... when i first got my car, it would fog up even if it was hot outside... after i cleaned it really good, it didn't do itso much.

i'd also check if there was water leaking somewhere... now that it's starting to rain, i've been keeping the heat set at it's hottest, with the AC on, to hopefully dry up as much water as possible.

hope that helped