Circuit/System Description
WARNING: This page is about a different car, the 2014 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
For headlamp operation, the body control module (BCM) monitors two signal circuits from the headlamp switch. With the headlamp switch in the PARK LAMPS position, the headlamp switch park lamps ON signal circuit is grounded, indicating that the park lamps have been requested. When the headlamp switch is in the HEADLAMP position, both the headlamp switch park lamps ON signal circuit and the headlamp switch headlamps ON signal circuit are grounded. The BCM responds by commanding the park lamps and headlamps ON.