Audi A4 B6 VW Passat B6 Xenon Headlight Module Ballast Control Unit 3D0907391B

Audi A4 B6 VW Passat B6 Xenon Headlight Module Ballast Control Unit is a specialized lighting system component designed to operate xenon headlights in Audi vehicles and selected VW group models. It provides stable power supply to the xenon burner, which translates into a uniform light beam and safe visibility on the road. Thanks to its design compliant with factory standards, it is a solution technically matched to original installations.

Specifications and technical data

• SKU: 3D0907391B
• Mark: Audi
• Condition: Used
• OEM Part Number: 3D0907391B
• Substitutable numbers: 3D0907391B, 3D0 907 391 B
• Location on the vehicle: Front, Left, Right
• Part type: Headlight Ballast
• Category: Headlight Ballasts & Ignitors

Application and function in the lighting system

The described ballast is responsible for generating the high voltage necessary for ignition and subsequent stabilization of xenon lamp operation. This component works with the front headlights, ensuring:

• proper xenon burner start-up without delays,
• maintenance of stable light intensity while driving,
• reduction of flickering and drops in headlight brightness.

Due to its dedicated design for a specific group of vehicles, the ballast integrates with the factory electrical installation and lighting control systems, which facilitates diagnostics and subsequent operation.

Compatibility and vehicle placement

The ballast has been designed for installation in the front part of the vehicle, with the possibility of use on both the left and right sides. Such a solution simplifies part selection during service – one type of component can serve both sides of the vehicle, provided the headlight construction is consistent with the factory standard.

Placement in the immediate vicinity of the headlight shortens the path of high-voltage cables and reduces energy losses, which promotes stable system operation. At the same time, it facilitates service access during replacement or diagnostics, without the need to interfere with other components.

Product characteristics and condition

The offered ballast belongs to the Ballasts and igniters for lamps group, i.e., components responsible for controlling and powering light sources in xenon headlights. The product comes from dismantling and is marked as used, which allows for economical repair of the lighting system while maintaining compliance with factory solutions.

Choosing a used component of this type is particularly beneficial for vehicles operated for many years, where the priority is reasonable service cost while maintaining correct lighting performance parameters. The ballast maintains a design consistent with the manufacturer's original standards, which promotes seamless integration with the existing installation.

Benefits of using an original xenon ballast

Using a ballast dedicated to the Audi A4 B6 and VW Passat B6 allows for reducing the risk of typical problems associated with improperly selected replacements, such as light control unit errors, unstable lamp operation, or electrical system interference. Key advantages include:

• compliance with the factory installation – matching original connectors and electrical parameters,
• stable power supply for the xenon burner,
• maintenance of proper light distribution and color in the headlight,
• possibility of using the existing wiring harness without modifications.

Thanks to this, the ballast is a practical solution for users who want to restore full efficiency to the xenon lighting system without interfering with the vehicle's original construction.

Technical support and additional information

When selecting elements from the lighting electronics group, it is worth paying attention to the compatibility of markings and the intended use for a specific vehicle model. In case of doubt, it is helpful to compare the factory-installed ballast with the offered product and consult a service specializing in xenon systems.

If you are planning a comprehensive repair or modernization of the front lighting zone in your Audi and need other elements from the same group, such as ballasts, igniters, or headlight control modules, check the available parts in the Audi lamp ballasts and igniters category.

Additional tips regarding the cost-effectiveness of using used electronic components in a car, including control modules and other subassemblies, are provided in the article: The second life of electronics – when is it worth choosing used controllers and modules. In the context of general vehicle operation and electrical system diagnostics, the guide on alternators may also be helpful: When is it worth replacing an alternator with a used one – a practical guide.