i got my s13 from a back lot from a used car dealership for cheap(don't know how long it was sitting there) and when i turned on the ac, there was this horrible smell which i thought to be mildew or something inside of the ducting. I had planned on getting some of that AC freshener stuff from the dealership, but instead I started taking stuff appart to start my RHD swap. Anyways, there was also this sound when i turned on the fan which i thought to be pine straw in the blower motor. Never did i think the two had anything to do with each other. then i found this don't think an air freshener would have fixed that...