Do you run your AC a lot, when you first turn on your AC do you get that mildew smell if so, your AC Condenser needs to be flushed. You can take it to the dealer to have it flushed or buy a kit at auto zone an do it yourself. The water that drips from your car why your AC is on comes from up inside a hose and from the Condenser, that water sits up inside of those areas and when you start your car an turn on your AC it comes through the vents and that's the smell. The kit will flush all the crap out of the condenser, remember this, if you do it yourself, it mite take 1 or 2 flushing to get it clean. Hope this helded