Mercedes W164 W251 Fuse Box Relay Module Control Unit A1645403572

Mercedes W164 W251 Fuse Box Relay Module Control Unit is an original electrical system component designed for the brand's SUV and VAN models. As part of the Fuses and fuse boxes group, it is responsible for the organized distribution of power and the protection of key vehicle circuits. Using an OEM component allows for a technically correct replacement of a damaged fuse box without interfering with the factory wiring architecture.

Specifications and technical data

• SKU: A1645403572-2
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1645403572
• Substitutable numbers: A1645403572, A 164 540 35 72
• Part type: Fuse Box
• Category: Fuses & Fuse Boxes

Purpose and function in the electrical system

The fuse box used in Mercedes W164 and W251 series vehicles serves as a central power distribution point for many electrical consumers. It is responsible for:

• organizing circuits protected by fuses and relays,
• a stable connection between electrical wiring harnesses,
• protecting sensitive systems from the effects of short circuits and overloads.

Thanks to its factory design, the module maintains compatibility with the original electrical diagram, which facilitates diagnostics and subsequent service.

Construction and advantages of the original fuse box

The offered fuse box belongs to the Fuses and fuse boxes group, meaning it was designed specifically for operation in the demanding environment of the engine bay or vehicle interior. The design provides:

• dedicated slots for fuses and relays,
• connectors matched to factory Mercedes wiring harnesses,
• a housing adapted for installation in the location provided by the manufacturer.

Such a solution reduces the risk of incorrect connection, minimizes voltage drops at connections, and supports the stability of comfort, safety, and engine control systems.

Benefits of using an original used component

Choosing a used OEM fuse box for a Mercedes allows you to combine economic aspects with maintaining the factory operating parameters of the installation. Key advantages include:

• compatibility with the factory installation – no need for wiring modifications or custom adapters,
• maintaining the original layout logic of fuses and relays,
• the possibility of a direct replacement of a damaged module with a functional equivalent.

This approach shortens repair time, facilitates the work of an auto electrician, and reduces the risk of subsequent problems with the power supply of individual circuits.

Selection and application in service practice

To correctly select a fuse box for a specific Mercedes vehicle, service practice utilizes manufacturer markings, reference numbers, and vehicle data. The use of the correct module is particularly important in cars equipped with extensive comfort and safety systems, where differences in configuration can affect the supported circuits.

In workshops specializing in the Mercedes brand, this type of fuse box is often used as a replacement part for damage caused by flooding, overheating, or long-term wear. A used OEM component allows for restoring the correct operation of the installation without the need for costly electrical system reconstruction.

If you are planning a comprehensive repair or upgrade of the electrical system area in your Mercedes and need other elements from the same group, such as modules with fuse sockets, additional distribution boxes, or housings with current paths, check the available parts in the Mercedes Fuses and fuse boxes category.

For those interested in the wider use of dismantled components in modification and repair projects, it is worth checking out practical tips regarding tuning and selecting used parts, described in the article Emotions and design – visual and mechanical tuning of a Seat using dismantled components.