My 1997 Nissan Altima air conditioning smells funky. on 1997 Nissan Altima

When I turn on my AC it smells like fungus or mold and when I turn on the heat it smells fine is there a way to fix that problem and if so please tell me how.

Asked by for the 1997 Nissan Altima
Whack it on full hot recycle close all doors n widows and let air con run with car turned on for about 5 to 10 mins burns out all nasty odours n mildew in system works in my 99 gt forester
This does not make sense. The problem is not being addressed here. Mold can be a serious health problem and it is ALWAYS caused by moisture. How is it drying the water going to help on ongoing bases? You need to find the source.