Mercedes W177 Window Regulator Lifter Mechanism Rear Right Door A1777300402

Mercedes W177 Window Regulator Lifter Mechanism Rear Right Door is an original component from the Window regulators and motors group, designed for the rear right window in the W177 body style. It ensures stable window guidance, proper power transmission, and safe operation of the entire lifting system in the rear passenger-side door.

Specifications and technical data

• SKU: A1777300402
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1777300402
• Substitutable numbers: A1777300402, A 177 730 04 02
• Location on the vehicle: Rear, Right
• Category: Window Motors & Regulators

Purpose and function in the vehicle

The presented mechanism is dedicated for installation in the rear right part of the body, in the rear passenger door. It is responsible for the precise guidance of the window along the rails and for the smooth raising and lowering of the glass within the factory window control system of the Mercedes W177 series.

Thanks to a design consistent with the vehicle manufacturer's solutions, the regulator works with factory door mounts, standard equipment, and control wiring, which facilitates installation and reduces the risk of operational issues after replacement.

Construction and technical characteristics

The mechanism belongs to the group of components responsible for transferring movement from the control system to the side window. The design is intended for operation in the rear right part of the body, taking into account the geometry of the door and the rails characteristic of the W177. The placement of mounting points and the kinematics of the mechanism are matched to the factory door panel and seals.

The regulator works with the window control system to ensure:

• stable window guidance throughout the full range of motion,
• even distribution of loads on the door structure,
• proper interaction with seals and the window frame,
• repeatable performance during repeated lifting and lowering cycles.

Benefits of using an original mechanism

Using an original window regulator in a Mercedes W177 allows you to maintain the factory operating parameters of the window system. Proper fitment for the rear right part of the body reduces the risk of window misalignment, excessive play, or improper closing. This is particularly important in vehicles equipped with advanced comfort systems, where correct window positioning also affects acoustic sealing and moisture protection.

Window regulators and motors in the original version also ensure predictable behavior in emergency situations, e.g., when anti-pinch safety features are activated, which is significant for the safety of vehicle occupants.

Condition, installation, and part selection

The item comes from disassembly and is offered as a used part, which allows for an economical repair of the window system while maintaining the manufacturer's original specifications. Before installation, it is recommended to perform a standard inspection of the door wiring, the condition of the rails, and the seals so that the newly installed mechanism can operate under optimal conditions.

When selecting a regulator for a specific Mercedes W177, it is worth verifying compatibility via the OEM number or interchangeable numbers, as well as the placement on the vehicle (rear – right side). This helps avoid mistakes and speeds up the service process.

Related components and technical knowledge

If you are planning a comprehensive repair or upgrade of the side window area in your Mercedes and need other components from the same group, such as lifting mechanisms, drives, or complete control units, check the available parts in the Mercedes Window regulators and motors category.

When selecting components for vehicle systems – especially in the case of parts coming from disassembly – it can be helpful to understand the principles of identification by factory numbers and how to evaluate the cost-effectiveness of a repair. These issues are discussed in more detail in the guide Why it is worth buying used gearboxes and engines – facts instead of myths, where you will find practical tips regarding working with used parts and their proper selection.