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:
Online Owner Center
Manage your vehicle (U.S.) at gmc.com. Click on “Owners,” then “Manage My GMC/Owners Login.”
Information and services customized for your specific vehicle — all in one convenient place.
...
License Plate Lamp
To replace one of these bulbs:
1. Reach under the rear bumper for the bulb socket.
2. Turn the bulb socket counterclockwise and pull the bulb socket out of the lamp assembly.
3. Pull the old bulb ...
Power Outlets
The accessory power outlets can be used to connect electrical equipment, such
as a cell phone or MP3 player.
There are four accessory power outlets in the following locations: below the
CD slot, ...