I've had a musty "rotten eggs" odor coming from the vents in my '95 GCL for about 2 months now. Its usually strongest on engine startup with the fan blowing on high, but then subsides somewhat after about 15 min. (maybe I'm just getting used to the smell). I've had a serious AC freon leak for the last 2 months as well, and I am working on finding where it is....but not sure if this is causing the odor or just a coincidence. I also recently replaced the radiator. I've owned the Jeep for 10 yrs. but this is the first time I've ever smelled this odor.
I've heard this could be mold & mildew growing in my AC vents, or maybe a bad heater core. It's definitely coming from the vent ducts...the carpet smells normal. Any ideas?