If your AC smells, there is an issue, depending upon the type of odor. Different smells are the result of different problems like: Feet-like smell: dirty or clogged AC. Exhaust fumes like smell: fluid leaks.  Gunpowder-like smells: short out circuit board or fan motor. Skunk-like smell: gas leak. Rotten eggs-like smell: animal remains inside the unit. Mildew-like smell: the presence of fungus in or around your AC unit.