Headlamp Switch
WARNING: This page is about a different car, the 2019 Ford F-550 Super Duty, 2019 Ford F-450 Super Duty, 2019 Ford F-350 Super Duty, and 2019 Ford F-250 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The headlamp switch has the dimmer switches integrated into it. They are momentary contact switches. The headlamp switch is monitored by the BCM. When the dim up or dim down button is pressed, the signal from the BCM is routed to ground indicating a request to increase or decrease the illumination brightness level.