As long as we are talking about moisture in your AC system there is a problem that you might want to consider. Not all of the moisture around your AC evaporator drips out to the ground. If the little drain hose is slightly plugged up, or you turn the car off under certain conditions, water will sit in the bottom of you AC box where it is dark and warm. This trapped water gets worse if you don't use your AC system very often. Sometimes little bits of dust and leaves that have been inadvertently sucked into the system also collect in this damp environment. It is a perfect breeding ground for molds, spores, and fungi to start to grow. Yuck! I know it sounds gross but it sometimes happens. Mostly you don't even know that this is even there. Usually the first sign of this problem is a damp ugly smell when you turn on the air. The best way to prevent this is to use the AC regularly and keep the drain hose clean. Not parking outside under trees is also helpful because it keeps debris from getting down threw the windshield vents and into the AC unit. Well, if you got the smell, how do you make it go away? There are several special produces that kill this mold and deodorize the system. They are available through your local auto part store. Basically they are spray cans, usually with some kind of a wand attachment that allows you to spray into the AC system. You turn on the AC fan full speed and put the system on fresh outside air venting. Then you spray the whole can of this stuff into the AC intake vents at the base of the windshield. The fan draws the cleaner through the system where it can go to work on killing the molds and mildew. I have also used lysol bathroom cleaner with good results. Try spraying some of the product into the interior dash vents this will get it in as many places as possible. Oh, turn off the fan first or it will just blow back all over you. Duh!