Mercedes Vito W639 Door Module Front Left N/S Control Unit ECU A6399003100

Mercedes Vito W639 Door Module Front Left N/S Control Unit ECU is a component from the Electronic control modules and controllers group, designed to handle the driver's door functions in this vehicle series. It enables the proper operation of electrical systems in the front left door, ensuring stable control and consistency with the vehicle's electrical installation. This is a solution for users who expect a proven component with factory performance characteristics.

Specifications and technical data

• SKU: A6399003100
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6399003100
• Substitutable numbers: A6399003100, A 639 900 31 00
• Location on the vehicle: Front, Left
• Category: ECUs & Computer Modules

Purpose and function of the module

The presented controller is dedicated to installation in the front left door of the Mercedes Vito W639 model. As a specialized module in the field of body electronics, it is responsible for coordinating the operation of electrical components in the door, such as mechanisms controlled from the driver's panel or security systems. Thanks to this, the vehicle maintains functional consistency, and door operation remains predictable and repeatable.

Benefits of using an original module

Using an original door control module in a Mercedes Vito W639 allows for maintaining compatibility with the factory electrical system architecture. Proper matching of connectors, operating logic, and control software translates into:

• stable communication with other controllers in the vehicle,
• correct response to signals from buttons and sensors in the door,
• reduced risk of errors in comfort and security systems.

For workshops and users, this means easier diagnostics, predictable installation, and a reduction in problems resulting from incompatible replacements.

Installation characteristics in the driver's door zone

The module is designed for installation in the driver's door area, which is a zone that is intensively used in daily driving. The location on the vehicle, defined as front – left side, allows for unambiguous identification of the mounting position and facilitates the selection of the correct component during repair or replacement. This allows for precise planning of service work, avoiding mistakes when selecting parts with a different purpose.

Product condition and application in service practice

The offered module is a used item, which in service practice represents a reasonable compromise between the cost of repair and maintaining factory performance characteristics. Such components are frequently chosen by workshops specializing in the Mercedes brand and by informed users who are looking for parts with a proven origin and parameters similar to those installed as original equipment.

If you want to better understand when choosing a used controller or comfort module is justified, it is worth reading the guide on our blog: The second life of electronics – when is it worth choosing used engine controllers, comfort modules, and parking sensors?

Mercedes electronic control modules and controllers – expansion and modernization

If you are planning a comprehensive repair or modernization of the body electronics area in your Mercedes and need other elements from the same group, such as comfort modules, passenger door controllers, or window control units, check the available parts in the Mercedes electronic control modules and controllers category.

Additionally, to better plan your repair budget and consciously use the used parts market, you can use the practical tips described in the article: Rising repair costs and the boom in used parts – how to save on car service?