But cars already have this. My 2014 Ford Edge has front/rear defrost/defog buttons and they work just fine. As "liability" said, the answer is warm, dry air whi

But cars already have this. My 2014 Ford Edge has front/rear defrost/defog buttons and they work just fine. As "liability" said, the answer is warm, dry air which happily works for both the defrost and the defog requests. Well, they worked fine, but my A/C just went out, so getting dehumidified air is a problem these days.