There are actually a few posts about this, if you do a search. Not bashing, but I had the same problem, AC was apparently supporting a mold farm in the truck, and ended up searching for the info to cure the stench. Solution wasn't there in black and white, but it gave me some ideas. Here's what I did;
1) Replaced in-cabin air filters. Didn't really help much because the filters were still pretty much new, but figured what the hell..
2) Used the household steam vac on the floor mats
3) Used steam vac detergent mix with a spray bottle, and a shop vac, and cleaned the interior seats and carpet of the truck. Allowed the truck to dry out completely for a day with the windows down.
4) Armor all / cleaned all the plastic surfaces.
5) Fogged the system with the AC off, fan on 4, windows closed, by spraying anti-bacterial air freshner in the inlet vent (next to windshield wipers). Fogging consisted of about 3 'treatments' of about 10 second sprays per treatment. The 3rd treatment I left the AC on.
Truck smelled HORRIBLE after that, for about a day, but the perfume sent went away and now there is nothing but a clean smell left. No more mold funk. I'm sure there is a better way to do this, but this worked for me.