Automatic Headlamps Operation
WARNING: This page is about a different car, the 2007 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.
When the ambient light sensor detects a low light condition, the BCM then applies a ground to the headlamp low beam relay control circuit. This engages the headlamp relay and applies voltage through the headlamp fuses to the low beam headlamps.