Display Dimming
WARNING: This page is about a different car, the 2005 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
Display dimming is controlled by the body control module (BCM) based on input received from the dimming potentiometer. The dimming potentiometer is connected between circuit 1359 and circuit 1381. The BCM monitors there inputs and provides a pulse width modulated (PWM) output at circuit 8 to operate the display lamps.