GM Service Manual Online
For 1990-2009 cars only

When it is dark outside, you can brighten or dim your instrument panel cluster lights using the DIM knob, located to the left of the steering wheel on the instrument panel.

Turn the knob clockwise to brighten the instrument panel cluster lights and displays. Turn the knob clockwise all the way to turn on the interior courtesy lamps. Turn the knob counterclockwise to dim the instrument panel cluster lights and displays and to turn off the courtesy lamps.