GM Service Manual Online
For 1990-2009 cars only

After you turn the ignition off and remove the key, you will still have power to such accessories as the power windows, audio steering wheel controls (if equipped), clock, sunroof (if equipped) and the radio for up to 10 minutes. The instrument panel cluster lights will stay on for a few seconds, then will go out. Once you open a door, the power will shut off.