That gap in the defroster is so that fresh/moister air from the cabin can be drawn into the defrost. Newer vehicles actually turn on the AC to add moister into the defroster in an attempt to not cause damage to the windshield from the temperature difference.
That gap in the defroster is so that fresh/moister air from the cabin can be drawn into the defrost. Newer vehicles actually turn on the AC to add moister into the defroster in an attempt to not cause damage to the windshield from the temperature difference.