Function and benefits: The headlight ballast regulates current and voltage to ensure the headlight bulb quickly reaches the working brightness and maintains it steadily, while protecting the bulb from overheating or overvoltage. Compatibility and part numbers: Adaptive Headlight Control Module with part numbers 63 11 7 182 396 and 63117182396 Direct Replacement for BMW E90 E91 E92 E93. Designed to work with GenXenon HID systems and to fit standard BMW headlight assemblies. Beam height stability: Dynamically compensates for pitch angle through the body attitude sensor to maintain a constant beam height, improving nighttime visibility and road alignment. Design and value: Exclusively designed for GenXenon to meet or exceed OEM specifications. Use case 1: Replacing a failed ballast in a BMW 3 Series E90/E91/E92/E93 to restore reliable brightness and protect the bulb during operation. Use case 2: Headlight service or where a direct OEMspec replacement is preferred to preserve beam accuracy and performance. Use case 3: Xenon headlight refurbishments or upgrades requiring OEMgrade control and dynamic beam height compensation for consistent light distribution on varying road pitches.