I was driving in heavy snow and using the heater for the windshield wipers, which is built into the windshield. The ice and slush continued to build on the wipers and I continued to use the heater. At one point, the snow had built up on the lower windshield and the heater was on. Suddenly, the windshield cracked all of the way across, above the heater and below the snow. The temperature difference must have caused this crack, as I was traveling only about 10 mph (as was everyone else) and no trucks or any type of vehicle in front of me that might have kicked up a stone. I took the car to Subaru and they said it was due a previous stone chip. I disagreed vehemently but they wouldn't replace the windshield. I have had to pay $325 to get it fixed. I feel this is something that is should be looked at. Perhaps the wiper heater shouldn't be activated when snow is on windshield. I do know that temperature difference is used in glass manufacturing to facilitate breaking at a certain point

- Wheaton, MD, USA