Circuit/System Description
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) supplies a voltage reference through the instrument panel dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the instrument panel lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated voltage through the instrument panel lamp supply voltage circuit illuminating the components listed below:
- Headlamp Dimmer Switch
- Tow/Haul Switch
- Traction Control Switch
- HVAC Control Module
- Driver Window Switch
- Driver Door Lock Switch
- Auxiliary Blower Motor Switch
- Passenger Window Switch
- Passenger Door Lock Switch
- Auxiliary Front HVAC Control Assembly
- Auxiliary Rear HVAC Control Assembly