2007 Lincoln MKZ Question: Erratic blower when defrost is turned on and water forming on front windshield.

Of course the dealership says there is no problem!! Whatever!! This has been an ongoing problem which they have been told about on several occasions. During the winter when the car is left overnight water droplets form on the inside front windshield over the right side dash. This is not regular fog but actual water drops. It only happens in the winter and not during the summer. As for the Defrost, when turned on first in the morning, it comes on full force sometimes and we cannot stop it at all even with the fan speed control button. It will make a sucking and hissing noise, stop by itself, and then start normally again all by itself. The car has normal heat and A/C other than these times. I do not think these things are normal as the dealership would have us believe. Any suggestions anyone? The car is still under warranty as well. Thanks for any help.