I used two products to clean and deodorize the AC system. Both of them are available at Autozone. (Turned out I didn't need them, read below)

This one you run the hose up into the evaporator drain hose to clean it out.
The AC drain hose is way back in the tranny tunnel. You can see it if you pull the vent on the driver's out that's located below the ignition.

You can reach from under the hood side feeling for it. Don't confuse the two drains under the cowl for it, you can't see it. It has a scupper fish mouth on the end. Once you find it shove the hose in.
Quest/Odor eliminator OE-1 at AutoZone.com - 1 reviews


This one you spray into the cowl and and AC vents.
Quest/A/C odor out fresh clean scent - Not for Hybrid vehicles with electrical driven compressors 760 at AutoZone.com



I can tell you though that in my case it wasn't the AC ventilation system causing the odor, it was in fact the carpet and or adhesive causing the funk and that's what was getting into the ventilation system. So even though I did both of these procedures they didn't help because they were the symptoms, not the cause.

This past weekend I pulled the windshield cowl to put the missing wiper grommet on and double check for clogs. There were a few leaves on the far passenger side but no clogged drains.

Try rubbing your hand on your carpet and take a whiff, if it's funky pull the seats, do the carpet shampoo and MOB like I did. I recommend pulling the cabin filter out and put the cover back on doing the MOB.
Hoover Max Extract Dual V WidePath Carpet Washer-F7412900 - The Home Depot


It's the only thing that worked for me.