Circuit/System Description
WARNING: This page is about a different car, the 2007 Chevrolet Monte Carlo and 2007 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
When the interior lamps dimming switch is activated, a variable voltage signal is applied through the instrument panel lamps dimmer switch signal circuit to the body control module (BCM). The BCM then applies a variable voltage pulse width modulated (PWM) signal through the LED dimming supply circuit to the HVAC control head, radio, driver information center (DIC) switch, cruise control switch and the steering wheel controls.