I have a 1999 9-3. When I turn on my air, just the blower, there is a weird smell that comes out. Sort of musty, dirty smell. If i turn the A/C on, the smell gets much more intense. Smells really bad, musty, almost like a burning smell. It's hard to describe. The heat works, but smells bad. The A/C blows air that isn't cold at all, and smells even worse. Wondering if anyone had any ideas as to what this could be. I have no idea.

 

could be a few things....the AC smelling even worse could be a busted evaporator, but I'd start looking at the cabin air filter first and than following the HVAC system down...I did a complete rebuild/wash of my hvac and sure glad I did it.