Evidently, the drainage system for the vehicle is plugged and will not allow excess water/moisture from the A/C unit to drain. This causes the windows, especially the windshield, to fog up during the winter months while using the defrost cycle. You can't keep the windshield, or ANY of the windows clear during the winter months, especially when it snows and you are trying to stay warm with the heater. Ii evidently throws the trapped moisture from the previous season onto the windshield. Could use some help on this if there is a fix for it. Tried to locate the drain myself, believe I did, but could not get anything into it to see if it were clogged.