in my car the drainage for the air conditioner is under the car. One on each side of the transmission tunnel. If you don't see any condensation water under the vehivle, you are probably looking at clogged a/c drainage tubes. Just get under your car and use a long wire, run it through the drainage tubes VERY CAREFULLY! That should work!
OR
through the same drainage tubes, you can use a long plastic/rubber hose and introduce clorox or whatever odor/mildew eliminator you want to use. Read the label to avoid damamge to plastic, evaporator, etc...
