Mercedes W166 Rear Door Wiring Loom Harness Left Right N/O/S A1664407532

Mercedes W166 Rear Door Wiring Loom Harness Left Right is an original, factory-spec electrical wiring harness designed for installation on either the left or right side of the rear bodywork. As part of the Cables, harnesses, and connectors category, this component ensures a proper electrical connection between the body modules and door equipment, resulting in stable operation of comfort features. It is a practical solution for users looking to restore full functionality to their Mercedes electrical system without interfering with the original wiring architecture.

Specifications and technical data

• SKU: RHD-A1664407532
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1664407532
• Substitutable numbers: A1664407532, A 166 440 75 32
• Location on the vehicle: Rear, Right, Left
• Part type: Body Harness
• Category: Wiring Harnesses, Cables & Connectors

Purpose and vehicle placement

The presented harness is dedicated to the rear body section of the Mercedes W166 model and can be used on both the left and right sides. This makes it suitable for electrical system repairs in the rear doors regardless of the vehicle side, facilitating the selection of the correct component during service.

The element has been designed as an integral part of the factory installation, maintaining proper wire routing and connector placement. This allows for the restoration of the original harness path, which is essential for durability, safety, and proper communication with control modules.

Technical and functional characteristics

The door harness is responsible for transmitting signals and power to components located in the rear doors, such as window controls, central locking, or lighting. The connectors used are matched to the factory sockets in the body and doors, enabling plug-and-play installation without the need for modifying the wiring.

The original design ensures:

• consistency with the vehicle's factory electrical diagram,
• appropriate length and geometry of wires for the rear left and right sides,
• compatibility with dedicated mounting points in the doors and pillars.

As a result, the harness allows for precise restoration of factory operating conditions, reducing the risk of malfunctions resulting from improper wire routing or the use of non-original solutions.

Condition of the item and benefits of using a used part

The offered harness is a used item, sourced from dismantling, which provides a reasonable compromise between repair costs and maintaining original quality. In the case of wires and connectors, factory components often provide a better fit than aftermarket replacements, which is particularly important in vehicles equipped with extensive comfort electronics.

Using an original, used harness allows you to:

• maintain compliance with the Mercedes factory electrical architecture,
• reduce installation time thanks to ready-made connectors and mounting points,
• minimize the risk of installation errors associated with modifying wires.

Professional use in service and repairs

Mercedes W166 Rear Door Wiring Loom Harness Left Right is particularly useful for post-accident repairs, replacing complete doors, or fixing faults related to broken wires in the door grommets. By maintaining the original design of the wires and connectors, the component fits well into the working standards of professional services specializing in the Mercedes brand.

In workshop practice, such a harness allows for:

• quick replacement of a damaged section of the installation without the need for soldering many individual wires,
• easier diagnostics – clear wire routing and factory colors make it easier to trace signals,
• maintaining high reliability of the electrical system in the rear of the vehicle.

Expansion of the offer and additional materials

If you are planning a comprehensive repair or upgrade of the body electrical installation area in your Mercedes and need other elements from the same group, such as additional door harnesses, connectors, or wire sections, check the available parts in the Mercedes Cables, harnesses, and connectors category.

For users considering a wider range of service work on the vehicle, including the selection of used components, the following guide article describing structural differences and practical aspects of using aftermarket parts may be helpful: Standard vs. sports suspension – design differences and is it worth buying used suspension parts?.