Assuming you mean moisture on the INSIDE of the windshield.. it is very most likely a leaking heater core or some other form of coolant leak into the passenger cabin. The reason it doesn't do it when the window is cracked is because it equalizes the temp and humidity on both sides of the glass. That's just basic science. In other words, leaving the window cracked probably has nothing to do with what is involved with the moisture to happen in the first place. It is just treating the symptom and not the problem.
Heated air is coming up the vents on the inside. If it has enough moisture, it will condense on the relatively cooler windshield. The same thing happens when there is warm moist air being circulated inside the car, and the outside air is cold.
It depends on the size of the crack. Windows cannot have any broken glass or cracks greater than 1 inch in the windshield wiper area, no cracks greater than 2 inches outside of it or any cracks longer than 3 inches that extend into this area.
Did you try moving the wipers arms a notch or two so when they start they are not at the bottom of the windshield but rather an inch or so above the bottom edge of the windshield to make them sweep farther to the outside?
I THE WINDSHIELD
To eat fish
The A/C runs to help defrost the windshield by removing moisture from the air. The fans run to help the cool off the condenser.
"A bright sunrise" could rhyme with "outside" and reference a good morning.
They are usually located in the cowl----the slotted area right below the outside of the windshield.
If you look through the windshield from OUTSIDE on the DRIVERS SIDE you will see the VIN plate near the base of the windshield on top of the dash
Insulated glass does help to prevent the build up of moisture on the outside of glasses. However, in with any weather, you are bound to find some type of moisture content on them, especially in rainy, foggy and snowy weather.
the defroster is actually your a/c. it doesn't run much when it's cold outside but it works with your heater to remove the moisture from inside the car. blowing warm dry air on the windshield. just like it removes the moisture (humidity) from inside the car in the summer. the difference is the temp. you have it on. even if the a/c don't work, the heater will still do the job, just not quite as well.
Lower left corner of the windshield, viewed from outside.