I have a 1998 Honda Civic LX, which didn't come with a cabin air filter. It has air conditioning but no filter, which makes no sense but that's how they supposedly were until 2001. When I turn my AC on, I can smell mold for the first few seconds it's on, then I can't smell it anymore.
I wondered about replacing the cabin air filter but it doesn't exist. That was my first idea; maybe the filter itself is moldy. I looked all around the fabrics and porous materials for any signs of mold, with no luck. The only thing I can imagine would be moldy in the vent system is the insulating wrap around the ducts, in which case I'd have to pull the dash.
If it isn't that, is there any way to kill the mold inside the ducts? Is there some method of maybe running a fungicide like bleach through the cabin intake without it spraying everything in the car when I turn the blowers on?