BMW G20 G21 LCI Rear Door Wiring Loom Harness Cable Left Right N/O/S 5A4A7B1

BMW G20 G21 LCI Left Right Rear Door Wiring Harness is an original electrical installation component designed for the left and right rear doors in facelifted BMW 3 Series models. A used, factory harness ensures consistency with the original wiring, facilitating installation and minimizing the risk of compatibility issues. This is a practical solution for those looking to restore full functionality to door electronics after body repairs or door replacement.

Specifications and technical data

• SKU: 5A4A7B1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 5A4A7B1
• Substitutable numbers: 5A4A7B1, 61125A4A7B1
• Location on the vehicle: Rear, Right, Left
• Part type: Wire Harness
• Category: Wiring Harnesses, Cables & Connectors

Application and Function in the Vehicle

The presented harness belongs to the Cables, Harnesses, and Connectors group and is responsible for transmitting signals and power between the rear doors and the rest of the car's electrical system. Its placement in the left and right rear door areas allows for the operation of functions such as window control, central locking, and other electrical components designed for the specific BMW G20/G21 LCI model. By maintaining the original wiring architecture, it can be seamlessly integrated into the factory body connectors.

Construction and Compatibility

The harness was designed by BMW as a component tailored to the specific facelifted generation of the 3 Series, with appropriate wire lengths, connector layouts, and rear door grommets. Proper routing of wires in flexible sections between the door and the body pillar minimizes the risk of chafing and damage during repeated opening and closing of the doors. The use of original connectors allows for near plug-and-play installation, without the need for electrical system modifications.

Benefits of Using an Original Harness

Choosing a used, factory wiring harness for the rear doors in a BMW G20/G21 LCI is a solution that maintains the consistency of the electrical system with the rest of the vehicle. Original connectors, correct wire gauge, and compatibility with factory mounting points contribute to the stable operation of electrical systems within the doors. This is particularly important for repairs after collisions, door replacements, or restoring full functionality of equipment after previous unprofessional modifications.

Service Purpose and Installation

This wiring harness is intended for service applications in facelifted BMW 3 Series G20/G21 vehicles, specifically for the left and right rear door areas. It is suitable for replacing damaged wiring as well as for completing doors sourced from another vehicle. A used part allows for optimized repair costs while maintaining the factory electrical system concept, which is beneficial in terms of durability and future fault diagnostics.

If you are planning a comprehensive repair or upgrade of the door electrical installation area in your BMW and need other components from the same group, such as additional harnesses, cables, or connectors, check the available parts in the BMW Cables, Harnesses, and Connectors category.

For those considering broader vehicle modifications using proven aftermarket components, an article describing a practical approach to selecting components may be helpful – more information can be found in the material Best Used Parts for Tuning Your Car.