Reactivation for Subsequent Owners
Push 
and follow the prompts to
speak to an Advisor as soon as
possible after acquiring the vehicle.
The Advisor will update vehicle records and will explain the OnStar service offers and options available.
See also:
Why Safety Belts Work
When you ride in or on anything, you go as fast
as it goes.
Take the simplest vehicle. Suppose it is just a
seat on wheels.
Put someone on it.
Get it up to speed. Then stop the vehicle.
...
Certification Label
A vehicle specific Certification label is found on
the rear edge of the driver door.
The label shows the gross weight capacity of your
vehicle, called the Gross Vehicle Weight Rating
(GVWR). ...
Rear Storage
Pull down the armrest. Push the button to lift the cover. Close the cover before folding the armrest up. ...