Mercedes W166 Fuse Relay Box Fusebox Housing Cover Unit 3.0 Diesel A1665400224

Mercedes W166 Fuse Relay Box Fusebox Housing Cover Unit 3.0 Diesel is an original electrical system component designed for diesel engine models. This used housing provides proper protection for the fuse module against moisture, dirt, and mechanical damage, which translates into stable operation of the electrical systems in the vehicle. This is a solution for users who want to maintain the factory design and secure fitment of parts for a specific body version.

Specifications and technical data

• SKU: A1665400224-1
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A1665400224
• Substitutable numbers: A1665400224, A 166 540 02 24, A 166 540 02 24 64, A166540022464, A 005 545 97 01, A0055459701
• Fuel type: Diesel
• Part type: Fuse Box
• Category: Fuses & Fuse Boxes

Purpose and function of the component

The described fuse box with housing and cover is dedicated to Mercedes W166 class vehicles with a 3.0 Diesel engine. Its task is to physically secure the fuse assembly and organize the electrical wiring harnesses in the engine compartment or inside the body (depending on the specific car configuration). Thanks to this, critical electrical components operate in controlled conditions, which limits the risk of short circuits, contact corrosion, and unplanned power interruptions. The element belongs to the Fuses and fuse boxes group, i.e., components responsible for protecting electrical circuits against overload. A properly selected housing is important both from the point of view of safety and subsequent diagnostics and service.

Compatibility and identification by numbers

The presented part is marked with an OEM number and has assigned interchangeable numbers, which facilitates its unambiguous identification in the manufacturer's catalogs and service systems. To ensure fitment to a specific Mercedes W166 with a diesel engine, it is worth verifying compatibility by part number or by the vehicle's VIN. Such an approach minimizes the risk of purchasing an unsuitable housing and speeds up the installation process. If you are upgrading or repairing the electrical system in a car with a diesel engine, selecting the right components by catalog numbers is just as important as in the case of fuel system elements. If you need broader diagnostics of the power unit and fuel supply, the following material may be helpful: Fuel system – injectors, pumps, and fuel tank: maintenance and regeneration.

Technical characteristics and installation

The fuse box housing was designed by the Mercedes brand with the specific spatial layout of the engine compartment in 3.0 Diesel versions in mind. Properly shaped mounts, wire routing, and cover geometry allow for stable attachment and proper sealing of the fuse assembly. Thanks to this, the installation proceeds in an orderly manner, without the need for modifications or forcing the element into place. The used part retains its original design, which promotes compatibility with factory brackets, harnesses, and connectors. In practice, this means that after confirming compatibility by OEM number or interchangeable numbers, it can be treated as a plug-and-play solution within a given W166 variant.

Practical application and benefits of replacement

Replacing a damaged or deformed fuse box housing is recommended in situations where there has been:

• cracking of the cover and loss of tightness,
• damage to the latches making it difficult to close,
• traces of overheating in the mounting area,
• interference with the electrical system after a collision or bodywork repairs. Selecting an original component allows you to restore the factory routing of harnesses and the proper arrangement of fuses, which facilitates later service work. Stable mounting and protection against external factors translate into lower susceptibility of the installation to failures related to moisture or dirt.

Support with selection and other installation elements

If you are planning a more extensive repair of the electrical system in your Mercedes, it is worth considering a review of other circuit protection elements as well. For this purpose, it will be helpful to browse the assortment in the Fuses and fuse boxes category, where you will find related components for various models and engine configurations. Additionally, for comprehensive maintenance of a vehicle with a diesel unit, it is worth using guide materials. You can find expanded knowledge on diagnostics and the selection of consumable parts in the article: a practical guide to diagnostics and part selection in modern automotive systems. Thanks to this, you will more easily plan service work, combining the replacement of electrical elements with the inspection of key diesel engine components.