GM Service Manual Online
For 1990-2009 cars only

The switch on this lamp has three positions. The ON position will turn on the light. The DOOR position will turn on the light whenever a door is opened or when the instrument panel brightness thumbwheel is moved up. The OFF position will shut off the lamp completely, even when a door is opened. If your vehicle is equipped with a sunroof, the dome lamp also has reading lamps for the rear seat passengers. Press the left switch for the left reading lamp and the right switch for the right reading lamp.