GMC 2006 Sierra - Manual (Page 110)

Windows
{ CAUTION:
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.
Manual Windows
Turn the hand crank on each door to manually raise or
lower the manual windows.
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