For the past few weeks all my windows inside my car will fog up within minutes of starting my car with the heater on. I dont see any coolant leaks inside or out of the car. If my heater core was bad wouldnt it be leaking somwhere? I can kind of smell a very faint odor of coolant but I just dont see any leaks!!! Also, could the heater control valve not be working properly and cause problems like this? The heat in the car works great otherwise it blows nice and hot air. I am clueless to what is going on. Any help would be greatly appreciated.