GM Service Manual Online
For 1990-2009 cars only

This feature is designed to protect the vehicle's battery against drainage from the interior lamps, trunk lamp, glove box lamp, or the garage door opener. When the ignition is turned off, the power to these features will automatically turn off after 10 minutes (three minutes if a new car has 15 miles (24 km) or less). Power will be restored for an additional 10 minutes if any door is opened, the trunk is opened or the courtesy lamp switch is turned on.