Windshield Deice Mode
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
After the engine has run for more than 10 seconds, the BCM sets a targeted generator output voltage of 13.8 volts if the calculated ambient air temperature is less that 0°C (32°F). The BCM will stay in this mode until the engine coolant temperature (ECT) reaches 75°C (167°F) for 10 minutes.