I have this problem big time, but I unfortunately caused it myself. My truck is sealed completely, and I mean air tight. When it rains and I got to my truck, no condensation on the inside. But when it rains and I get into my truck with my wet boots on, and close the door when I leave, I always come back to massive amounts of condensation in the truck on everything. I tested my theory a couple of times, with a cooking pan and water sat on my floor mat below the drivers seat. It's amazing how "sealed" we can get our vehicles with some type of audio sound deadener. There are so many large open holes that allow the moisture out, but in order to achieve higher numbers and quality, we inadvertently close up the only ways moisture has to escape the interiors of our vehicles. Just don't fart.