OK. Here it is - Foam cleaning of the AC evaporator. If you have a funky odor coming from your vent system, chances are you have mold growing in the evaporator. There are several steps to cleaning it and the odor out. First, remove the cabin air filter which you have probably never changed - yuck. On the driver's side center console, open the cabin air filter access panel and remove the cabin air filter - Like this:
cabin-air-filter-t321326.html
While the filter is out, use a vacuum to get as much debris as possible out of the cabin air filter slot.
Then close up the filter access panel without putting a new filter in.
Then on the passenger side center console, remove the trim panel and locate the AC drain tube

Pull the tube off of the drain and then feed the spray tube from a can of Kool-It Evaporator and Heater Foam Cleaner as far into the evaporator housing as you can

Shake the can and then spray the entire contents into the evaporator while keeping the can upright. You should probably hold your thumb over the drain hole so that the foam doesn't come out all over your carpet.
When the can is empty, replace the drain tube. Wait 20 minutes for the foaming cleaner to clean and condense and drip out of the drain hole. - Oh, you probably want to put a container under the car where the drain hose is to catch the fluid as it drains.
After 20 min, Install a new cabin air filter, turn on the car and run the blower for 5 minutes with fresh air, with the AC off.
If you still have some funky smells, you may need to disinfect the vents. To do this, you can simply spray Lysol into the vent under the hood near the windshield. You can also put the vents on recirculate and spray the Lysol into the vents at the driver's and passenger's foot area.
Here's a link to Kool-It:
http://www.amazon.com/Kool-It-96030-Eva ... B0007PHD0S
You can also use Einszett Klima Cleaner Professional:
http://www.amazon.com/gp/product/B0002Z2MKO
But Kool-It is cheaper and often able to be found locally. I bought it at O'Reilley's Auto