Circuit/System Description

WARNING: This page is about a different car, the 2007 Saturn Sky. However, it is still accessible from the selected car via links, so may be relevant.

The body control module (BCM) receives an input from the instrument panel (I/P) dimmer switch. The BCM provides the I/P dimmer switch with battery voltage and a low reference. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the BCM. This input determines the intensity level of the backlighting illumination. The driver may change intensity of the backlighting by positioning the I/P dimmer switch between the minimum and maximum settings. The BCM will default to full intensity if the input from the I/P dimmer switch is not within the specified values. The backlighting illumination intensity is controlled by the BCM by varying the pulse width modulation (PWM) voltage that feeds the dimming signal circuits of the individual lamps. All interior backlighting lamps are permanently grounded.