Rearview Mirror problems of the 1996 Ford Crown Victoria

I purchased a used 1996 Ford Crown Victoria from cal worthington Ford in alaska a little less than three years ago. When I purchased the car, I also purchased a premium warranty policy and the vehicle is still under warranty. The vehicle has heated rear-view mirrors. A little over two years ago after a snow storm, the passenger-side rear-view mirror cracked straight down the middle. Snow had covered the mirror and I assume when the mirror heated, it cracked. Four months ago after another snow storm, the driverã‚??s side mirror cracked straight down the middle. Once again, it was cold and when the mirror started heating up it cracked. Please note - I always brush the snow off my car before I warm it up. Request ã‚?? Ford motor CO. Replaces the mirrors at no cost to me I contacted cal worthington Ford and asked them to replace the mirrors under warranty and they refused. I have two reasons for this request: 1) the mirrors are defective and pose a safety hazard. The mirrors cracked because of a poor engineering design. The mirrors didn't crack because of negligence caused on my part. 2) the car is still under warranty.