Interior Dim Pot
WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The BCM uses this input to determine the requested level of the instrument panel dimming lamps. When full intensity is requested, the scan tool will display less than 1 volt. When full dim is requested, the scan tool will display approximately battery voltage. The voltage will vary within this range depending on the position of the lamp dimmer switch.