GM Service Manual Online
For 1990-2009 cars only

The interior lights control is located on the overhead light. To change the interior lights setting, slide the switch to one of the following positions:

OFF:  This position turns the light off.

ON:  This position keeps the light on all the time.

(Door):  This position turns the light on when any door, the liftgate or the liftglass is opened. The light goes off when all the side doors, the liftgate and the liftglass are closed.