Mercedes X166 Rear Window Lifter Regulator Motor Adjuster Right O/S A1666700104

Mercedes X166 Rear Window Lifter Regulator Motor Adjuster Right O/S is an original component from the Window regulators and motors group, designed for precise operation of the rear right window in an SUV body. This is a solution for users who expect stable mechanism performance, proper window guidance, and the preservation of the factory comfort system functionality.

Specifications and technical data

• SKU: A1666700104
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1666700104
• Substitutable numbers: A1666700104, A 166 670 01 04
• Location on the vehicle: Rear, Right
• Category: Window Motors & Regulators

Purpose and function of the component

The presented assembly is a combination of an electric drive and a regulation mechanism responsible for the smooth raising and lowering of the rear right window. Its placement in the rear part of the body on the passenger side allows for direct window operation from the door panel and the central comfort control module.

The component works with the vehicle's factory electrical installation, ensuring proper window movement speed, adequate pressure against the seals, and consistent performance under typical operating conditions. By maintaining the original geometry of the mounts and window guide points, it is possible to maintain airtightness and reduce wind noise while driving.

Benefits of using an original window regulator

Using an original regulator and motor in the rear right part of the body allows for consistency with the other components of the window system. In practice, this means:

• proper cooperation with factory comfort controllers and overload protection systems,
• stable window movement without jerking or unwanted play in the guides,
• maintaining the correct end position, which reduces the risk of leaks and rattling,
• easier diagnostics in the event of potential electrical system faults.

For the user, this means more predictable mechanism operation, improved acoustic comfort inside the vehicle, and a reduced need for additional adjustments after installation. The original design also facilitates future service, as the operating parameters are consistent with the vehicle manufacturer's specifications.

Installation characteristics and fitment

The regulator is designed for installation in the rear right part of the body, which simplifies the identification of the correct installation location. The mounting layout and motor position are adapted to the factory door paneling and window frame structure, allowing for the use of existing bolt points and original electrical wiring grommets.

When correctly selected for a specific vehicle, the installation process consists of:

• removing the door upholstery and disconnecting the old mechanism,
• transferring the window to the new regulator while maintaining the correct alignment,
• connecting the motor's electrical connector to the factory harness,
• checking the window's range of motion and performing any necessary end-position calibration.

This solution helps reduce vehicle downtime and minimizes the risk of additional structural modifications.

Condition of the component and operational aspects

The offered Mercedes X166 Rear Window Lifter Regulator Motor Adjuster Right O/S is a used part, which in practice means a favorable cost-to-functionality ratio while maintaining the original design. For many users, this is a reasonable alternative to new aftermarket replacements, especially for vehicles used daily, where both efficiency and repair economy are important.

To better plan your service budget and learn the arguments for choosing components from the secondary market, it is worth reading our expert guide: Why it is worth buying used gearboxes and engines – facts instead of myths. The selection procedures based on identification numbers and cost analysis contained therein also help in a conscious approach to purchasing other used sub-assemblies.

Complementary Mercedes Window regulators and motors

If you are planning a comprehensive repair or upgrade of the door and window area in your Mercedes and need other elements from the same group, such as front window drives, guide mechanisms, or additional control motors, check the available parts in the Mercedes Window regulators and motors category.