Window Lifter Mercedes W204 W212 1 Rear Left N/S Regulator Panel A2127301779

Window Lifter Mercedes W204 W212 1 Rear Left N/S Regulator Panel is an item from the Window Regulators and Motors group, designed to control the movement of the window in the rear left door. It ensures smooth raising and lowering of the window, which translates into comfort of use and proper operation of the window opening system in your Mercedes.

Specifications and technical data

• SKU: A2127301779-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A2127301779
• Substitutable numbers: A2127301779, A 212 730 17 79, EM
• Location on the vehicle: Rear, Left
• Category: Window Motors & Regulators

Purpose and function of the window lifter

The rear left window lifter in Mercedes W204 and W212 models is responsible for stable window guidance and transmitting the drive from the control mechanism. A correctly selected component guarantees:

• even window movement without jamming,
• proper window sealing in the closed position,
• consistent operation with the factory window control system.

Thanks to its dedicated placement in the rear left door zone, compatibility with the body structure and the window guides provided by the manufacturer is maintained.

Vehicle fitment and mounting parameters

The presented lifter has been designed specifically for Mercedes vehicles from the W204 and W212 series, taking into account the door geometry, mounting points, and window travel range. The placement on the vehicle described as Rear - left allows for clear identification of the correct installation side and reduces the risk of error when selecting parts.

The component belongs to the Window Regulators and Motors group, which means it works with the factory window control system, maintaining the original operating characteristics – both in terms of movement speed and opening range.

Performance characteristics and benefits of replacement

Using the appropriate window lifter in the rear left door allows you to restore full window functionality after a mechanism failure or operational wear. Replacing this component is particularly important when symptoms appear such as:

• irregular window movement or it getting stuck in the guides,
• the window dropping after closing the door,
• no response to button control despite the electrical system being functional.

Selecting the correct lifter dedicated to the W204 and W212 minimizes the need for mounting modifications and allows for the retention of factory mounting points. This solution is technically consistent with the door construction, which facilitates service work and shortens repair time.

Part condition and technical aspects

The offered window lifter is marked as Used, which in practice means that it comes from dismantling and has been verified for suitability for further use. For the user, this means the possibility of restoring the window mechanism's efficiency while maintaining a favorable cost-to-functionality ratio.

The component has a factory OEM part number and assigned interchangeable numbers, which facilitates clear identification in service catalogs and parts selection systems. Additionally, the product is marked in the warehouse system via SKU, which speeds up order processing and reduces the risk of logistical errors.

Mercedes Window Regulators and Motors – expansion and service

If you are planning a comprehensive repair or upgrade of the door zone in your Mercedes and need other elements from the same group, such as window lifting mechanisms, electric drives, or guides, check the available parts in the Mercedes Window Regulators and Motors category.

Technical support and service knowledge

When selecting consumables and repair parts for vehicles of various brands, it is worth using reliable sources of technical information. If you are interested in how potential engine unit failures can affect your car maintenance budget, read the article: Faulty BMW E90 engines: check what can ruin your budget!. This is a practical supplement to knowledge about car operation, also useful when planning broader service work.