Windows

WARNING!
Leaving children, helpless adults, or pets in a vehicle with the windows closed is dangerous.
They can be overcome by the extreme heat and suffer permanent injuries or even death from heat stroke. Never leave a child, a helpless adult, or a pet alone in a vehicle, especially with the windows closed in warm or hot weather.

The vehicle aerodynamics are

The vehicle aerodynamics are designed to improve fuel economy performance. This may result in a pulsing sound when a window is partially open. To reduce the sound, open another window or the sunroof (if equipped).

See also:

Battery Power Protection
This feature shuts off the dome lamps if they are left on for more than 10 minutes when the ignition is in LOCK/OFF. This helps to prevent the battery from running down. ...

Engine Drive Belt Routing
CTS V6 Engines CTS-V 6.2L V8 Engine ...

Rear Safety Belt Comfort Guides
This vehicle may have rear shoulder belt comfort guides. If not, they are available through your dealer. The guides may provide added safety belt comfort for older children who have outgrown ...