[quote name='Blade']That happened to my car, too, and I actually found mold when I took the seats and carpet out. Mine was a combination of a gap in the seal near the side mirrors, and a vent that wouldn't close.[/quote]
Exactly this happened to car I used to have. The rubber strip that holds the glass against the car had tears in it and water was getting in. Then mold was growing in the roof lining in the front side of my car.