Door Module Mercedes W204 W212 Rear Right O/S Control Unit Module A2129004414

Door Module Mercedes W204 W212 Rear Right O/S Control Unit Module is a specialized component from the Electronic control modules and controllers group, responsible for the operation of electrical systems in the vehicle's rear right door. Designed for Mercedes vehicles, it ensures precise control of door functions and consistency with the factory electrical system architecture.

Specifications and technical data

• SKU: A2129004414
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2129004414
• Substitutable numbers: A2129004414, A 212 900 44 14, KZ
• Location on the vehicle: Rear, Right
• Category: ECUs & Computer Modules

Purpose and function of the door module

The door module is installed in the rear right door area and is responsible for handling key electrical functions in this zone. In a typical configuration, it works with the body wiring harness, enabling proper communication with other controllers in the vehicle and maintaining the consistency of comfort system logic.

As an element from the Electronic control modules and controllers category, this component is an integral part of the vehicle's controller network, which allows for maintaining system stability and correct diagnostics using factory service tools.

Compatibility and vehicle integration

The module has been developed for Mercedes platforms of the W204 and W212 family, ensuring that its design and software are adapted to the electrical architecture of these models. Proper matching of connectors, housing, and control logic allows for installation in place of the factory component without the need for wiring modifications.

The vehicle placement specified as rear – right side facilitates proper identification of the component during parts selection and service planning. The correct choice of a door module has a direct impact on the proper operation of comfort and safety functions in the given body area.

Product characteristics and advantages of use

The offered item is a Mercedes brand product, which means maintaining factory quality standards and compatibility with vehicle systems. Using an original door module allows you to:

• maintain communication consistency within the vehicle's controller network,
• preserve predictable door function operation in accordance with the manufacturer's specifications,
• facilitate diagnostics and potential software updates at authorized service centers or specialized workshops.

The used condition of this component allows for an economical restoration of system efficiency while maintaining the original technical specification, which is particularly important for premium class cars, where compliance with the factory configuration is of great significance.

Professional selection and practical application

When replacing modules from the Electronic control modules and controllers group, it is crucial to match the component to the specific vehicle equipment version and its electrical configuration. In workshop practice, this means the necessity of verifying controller parameters, followed by installation in accordance with the manufacturer's procedures, taking into account potential adaptation or coding in the vehicle system.

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

Used OEM modules in premium cars

In the premium car segment, a repair strategy based on used OEM components is increasingly being used, which allows for combining rational costs with maintaining the original specification. In the context of brands such as Mercedes, BMW, or Porsche, properly selected electronic controllers and modules enable the maintenance of a high level of vehicle functionality without the need to resort to replacements with uncertain parameters.

More about the trend of using used original parts for premium cars and how to consciously plan repairs in the face of changes in the new components market can be found in the article Crisis in the new parts market? Why used originals for premium cars (BMW, Mercedes, Porsche) are the hottest trend in 2026.

Substantive support and knowledge development

Although the described module concerns the Mercedes brand, issues related to maintaining the character of premium vehicles and the importance of original components are common to many manufacturers. In the context of another premium brand, Audi, an interesting supplement to knowledge may be the material devoted to the role of factory parts in maintaining driving characteristics and the quality of onboard systems – you can read more about this in the article Audi and pure emotion. How do used parts help maintain the brand's DNA?.

By choosing Door Module Mercedes W204 W212 Rear Right O/S Control Unit Module, you are opting for a solution consistent with the vehicle's factory concept, which facilitates service, diagnostics, and long-term maintenance of electronic system consistency in your car.