GM Service Manual Online
For 1990-2009 cars only

If a door is open, a reminder chime sounds when the headlamps or parking lamps are manually turned on and the key is out of the ignition. To turn off the chime, turn the headlamp switch to off and then back on. In the automatic mode, the headlamps turn off once the ignition is in LOCK/OFF.

For vehicles first sold in Canada, if the parking lamps are turned on manually, the Daytime Running Lamps (DRL) will stay on.