Where is the drain for heater, a/c evaporator core? Is it just that little hole at the bottom of the housing? Working on 2012 chevy express 1500 v6 cargo van. Theres a terrible odor inside since i bought it 2 months ago. Removed all rubberized vinyl flooring, even the oem vinyl seat covers. Fumigated with chlorine dioxide too... idor comes right back. Hate to sell it due to odor!

 

Maybe you have dead rodents in the hvac system/ducting??

 

I asked where is the evaporator drain.