Also, consider that all the air that comes into the car goes via the cabin filter so it will be worth looking at the condition of this. They are very cheap and easy to change. My car smelt fusty and kept misting up, but all was fixed after i replaced it, including improved air circulation.

If it was definately electrical, check all the relays and fuses under the hood and in the fuse box located in the end off the dashboard, this at drivers side on my uk spec car.

Good luck!
Steve