My 2005 Mitsubishi Galant smells when AC is on?

I get this aweful musty moldy smell when the AC is on. What is causing this and what can I do. I guess maybe I should also check to see if its under warranty.

This is common, and nothing to worry about. A/C systems remove moisture form the air in your car, and not ALL of this moisture escapes to the ground like it should.

MY car does not have a cabin air filter, but yours MAY have one. Check it out.

look at what the cabin air filter seems

the smell will be coming from the heater box on it,you may have had a rodent get in their and die I it,or old debris has built up,and is causing it to smell bad,in majority of cases if its this bad you have to take off the heater box and clean it out,id attempt and see if this is covered under warranty,they may get it to meet the criteria under some part of it,good luck with it.