Volkswagen Polo 6R Golf Mk6 3-Door Window Lifter Switch Driver's Side 1K3959857A

Visual condition of the part 

The product shows signs of use visible in the photos. 

Volkswagen Polo 6R Golf Mk6 3-Door Window Lifter Switch Driver's Side is an original component from the Electronic control modules and controllers group, designed to control the electric windows on the driver's side in 3-door body styles. This factory-fitted switch, installed in the front part of the driver's door, ensures precise, convenient, and reliable operation of the window lifting and lowering mechanism.

Specifications and technical data

• SKU: 1K3959857B
• Mark: Volkswagen
• Condition: Used
• OEM Part Number: 1K3959857B
• Substitutable numbers: 1K3959857B, 1K3 959 857 B, 1K3959857A, 1K3 959 857 A
• Location on the vehicle: Front
• Category: ECUs & Computer Modules

Application and function in the electrical system

The driver's side window switch in 3-door Polo 6R and Golf Mk6 models acts as a local control module that transmits signals to the vehicle's electrical system. It is responsible for:

• controlling the window movement in the driver's door in up/down mode,
• precisely transmitting impulses to the electrical system,
• cooperating with other components of the window control installation.

Thanks to a design compliant with manufacturer standards, the switch maintains the correct operating characteristics and is matched to the electrical parameters of the factory wiring harness.

Construction, installation, and compatibility

The component is designed for installation in the front part of the driver's door, in the factory control panel socket. This means that it:

• fits the original mounting hole in the door trim,
• uses the factory electrical connector,
• requires no wiring modifications or interference with the door structure.

As a part from the Electronic control modules and controllers group, the switch works with other body modules, maintaining the consistency of the entire window control system.

Performance characteristics and benefits

Using an original driver's side window switch in a Volkswagen Polo 6R or 3-door Golf Mk6 allows you to maintain the consistency of the electrical system and ergonomic operation. Key benefits include:

• factory fitment to the door panel and vehicle installation,
• consistent operation with existing control modules,
• preservation of the original button logic,
• reduced risk of communication errors in the electrical system.

This solution is particularly beneficial when replacing a damaged switch, where maintaining original functionality and interior aesthetics is a priority.

Component condition and service application

The offered switch comes from disassembly and is intended for reinstallation in a vehicle where restoring the functionality of the driver's window control is required. This type of component is often used in professional workshops and services specializing in body electronics, where compliance with factory specifications and predictable behavior in the installation are essential.

If you are interested in the broader context of body module operation and want to better understand how similar control systems work in other brands, it is worth checking out the guide on multimedia systems and electronic modules for BMW: Driving pleasure for years – how to take care of iDrive systems and electronic modules in BMW 3 and 5 series models.

Expanding the control system in Volkswagen vehicles

If you are planning a comprehensive repair or upgrade of the door zone and window controls in your Volkswagen and need other elements from the same group, such as additional control modules, button panels, or controllers responsible for window operation, check out the available parts in the Volkswagen electronic control modules and controllers category.