GM Service Manual Online
For 1990-2009 cars only

These vehicle accessories can be used for up to 20 minutes after the engine is turned off:

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

These features will work when the key is in ON/RUN or ACC/ACCESSORY. Once the key is turned from ON/RUN to LOCK/OFF, these features continue to work for up to 20 minutes, or until a door is opened.