GM Service Manual Online
For 1990-2009 cars only

These vehicle accessories can be used for up to 10 minutes after the engine is turned off:

    â€¢ Audio System
    â€¢ Power Windows
    â€¢ Sunroof (if equipped)

Power to these features will continue to operate for up to 10 minutes after the key is turned to LOCK/OFF until a door is opened.