Mercedes W639 Battery Starter Alternator Wiring Harness Cable A6394403150

The Mercedes W639 starter and charging wiring harness is an original electrical system component responsible for connecting the battery, starter motor, and alternator. Thanks to its factory design, it ensures stable power supply to the starting system and correct battery charging, which translates to reliable engine starting and proper vehicle electronics operation.

Specifications and technical data

• SKU: rhd-A6394403150
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6394403150
• Substitutable numbers: A6394403150, A 639 440 31 50, KZ
• Category: Wiring Harnesses, Cables & Connectors

Application and Function in Mercedes W639

The offered starter and alternator wiring harness for Mercedes W639 belongs to the Cables, Harnesses, and Connectors category and is a key element of the current path between the battery, starter motor, and alternator. It is responsible for:

• transferring high starting currents from the battery to the starter motor,
• stable connection of the alternator to the vehicle's electrical system,
• minimizing voltage drops thanks to appropriately selected wire cross-sections,
• safe routing of wires in the engine bay according to the factory path.

By maintaining the original geometry and mounting points, the harness allows for correct cable routing, which reduces the risk of chafing, overheating, and electrical system malfunctions.

Construction and Advantages of the Original Harness

The harness was designed by the vehicle manufacturer with the demanding operating conditions in the engine bay in mind. It includes wires of appropriate diameter, factory connectors, and connection points matched to the Mercedes W639 components. The insulating materials used are resistant to temperature, vibrations, and contact with typical operating fluids.

Compared to aftermarket alternatives, the original wiring harness ensures proper length of wires, outlet angles, and terminal types, which facilitates installation and reduces the risk of installation errors. This is particularly important in high-current circuits, where any improper connection can lead to overheating and voltage drops.

Condition, Selection, and Installation

This item is a used part and is offered as a used wiring harness, which is a cost-effective solution for users looking for original components at a reasonable price. Before installation, a standard visual inspection of the insulation, terminals, and mounting points is recommended, as well as cleaning of electrical contacts according to good service practice.

To correctly select the harness for a specific Mercedes W639 model, it is advisable to use the manufacturer's markings and reference numbers assigned to this part. This helps avoid compatibility issues and ensures that the wires will fit the factory connection points in the vehicle.

Benefits of Using the Original Wiring Harness

• Factory fit for the Mercedes W639 electrical system.
• Appropriate current capacity for the starter and alternator.
• Thoughtful wire routing path, reducing the risk of mechanical damage.
• Compatibility with original vehicle connectors and ground points.
• Possibility of restoring correct operation of the starting and charging system after damage to the old harness.

Other Mercedes Cables, Harnesses, and Connectors

If you also need other Mercedes Cables, Harnesses, and Connectors for your vehicle, check out our dedicated offer: Mercedes cables, harnesses, and connectors. This will allow you to easily assemble the remaining electrical system components in one place.

Technical Support and Service Knowledge

When working on the electrical system, it is advisable to know the general principles of diagnostics and component selection based on manufacturer markings. Helpful information can be found in our guide: Fuel System – Injectors, Pumps, and Fuel Tank: Maintenance and Repair, which describes, among other things, a practical approach to identifying parts by OEM numbers and good service practices, also useful when working with the electrical system.