The engine redirects maximum heat to the windshield
The fan jumps to high speed automatically
Airflow is precisely angled to hit the glass
In many cars, the air conditioning turns on as well—not to cool, but to remove moisture, which melts frost faster
The result? Ice and fog start breaking apart within seconds instead of minutes.
In newer vehicles, this system is optimized to clear the windshield as quickly and safely as possible—often faster than scraping by hand.
Why So Many Drivers Never Use It
Surprisingly, a lot of drivers don’t know this feature exists—or they underestimate it.
Some assume it’s the same as turning the heat up manually. Others think it wastes fuel. And many simply never had it explained to them when they bought the car.
There’s also confusion between:
Front defrost (for ice and fog on the windshield)
Rear defrost (the grid lines on the back window)
Drivers often use one and forget the other—or don’t realize how different their functions are.
