Hi, I believe I've pinpointed the moldy smell in my A/C to the return vent. It makes sense because the previous owner at some point obviously had water ran down the A pillars, so it's most likely the smell is actually coming from under the floor carpeting. I looked down, but I can't seem to find the vent. Can someone please help out and take a pic of where it is? Thanks.

 

The passenger-side A/C return vent isn't _in_ the floor, at least not on my 2002. Just open the passenger door, kneel down so you see the side wall of the centre console, and you'll see it on the wall of the centre console near your left knee/left foot area.