Component Description: Ballast
WARNING: This page is about a different car, the 2018 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.
A ballast is located within each High Intensity Discharge (HID) headlamp assembly. The BJB provide voltage to the ballasts. The ballasts provide high voltage to the High Intensity Discharge (HID) bulbs when voltage from the BCM (low beam outputs) is detected.