BMW F20 F21 F30 F31 Rain Sensor Windscreen Light Solar Condensation Unit 7939173

BMW F20 F21 F30 F31 Rain Sensor Windscreen Light Solar Condensation Unit is an original BMW component responsible for the automatic control of wipers and lighting functions based on precipitation intensity and light levels. Thanks to this module, the wiper and lighting system operates more comfortably and predictably, improving daily driving convenience. It is a practical solution for drivers who expect stable performance from factory-fitted assistance systems.

Specifications and technical data

• SKU: 7939173
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7939173
• Substitutable numbers: 7939173, 61357939173, 9475147, 61359475156806745, 9321007, 61359321007, 9347396, 61359347396, 9387624, 61359387624, 9332180, 61359332180, 9388381, 61359388381, 6819590, 61356819590, 9354844, 61359354844, 9354226, 61359354226, 6814601, 61356814601, 9397911, 61359397911, KD
• Category: Additional Wiper & Washer Components

Purpose and function of the sensor

The presented rain and light sensor is designed for selected BMW F-series models, including the F20, F21, F30, and F31, where it works in conjunction with the factory wiper and lighting system. This component monitors conditions outside the vehicle and transmits signals to the body control modules, enabling automatic activation of wipers and lights at the appropriate moment. This allows the driver to focus on driving, while the system reacts automatically to changing weather and lighting conditions.

Integration with factory BMW electronics ensures consistent operation with other comfort and safety modules, without the need for additional adapters or wiring modifications, provided the vehicle is factory-equipped to work with such a sensor.

Identification parameters and compatibility

The sensor belongs to the Other wiper parts group, meaning it is a component supporting the windshield cleaning system rather than the wiper blade or drive mechanism itself. The product has a dedicated OEM part number and a set of interchangeable numbers, which facilitates precise identification and selection for a specific vehicle configuration. In practice, this means it can be used as a replacement in various equipment variants where the manufacturer has provided for this type of sensor.

To ensure compatibility, it is recommended to compare your existing component with the offered sensor in terms of manufacturer markings and the vehicle's installation type. This verification method minimizes the risk of incompatibility and speeds up the installation process.

Product condition and benefits of choosing used OEM

The offered rain and light sensor is in used condition, which in practice means it has been removed from a vehicle and verified for further serviceability. Choosing an original component from the secondary market allows you to maintain the factory operating characteristics of the system while reducing costs compared to purchasing a new part.

A used OEM element is a reasonable compromise between quality and price – especially in the case of advanced sensors, where compatibility with vehicle electronics is crucial. Stable operation of the automatic wiper and lighting system translates into greater driving comfort in rain, fog, or after dark.

To better plan your repair budget and learn about the possibilities of saving on original parts from the secondary market, it is worth reading the guide: Rising repair costs and the boom in used parts – how to save on car maintenance?

Installation and practical tips

The rain and light sensor is mounted within the windshield area, in the location provided by the vehicle manufacturer. When replacing, it is recommended to:

• check the compatibility of the wiring harness and connector,
• keep the windshield surface clean in the sensor's operating area,
• properly seat the sensor in the holder or mounting frame,
• perform a system calibration according to the BMW service procedure (if required for the specific model).

A correctly installed sensor ensures smooth switching of wiper and lighting modes, without accidental delays or incorrect reactions to changing conditions.

Expanding the wiper system in BMW

If you are planning a comprehensive repair or upgrade of the windshield area in your BMW and need other components from the same group, such as additional sensors, mounting elements, or covers related to wiper operation, check the available parts in the Other BMW wiper parts category.

For drivers who want to learn more about selecting used original components for popular models, the following guide may also be helpful: The best used car parts – a guide to the most frequently chosen original parts.

Summary

BMW F20 F21 F30 F31 Rain Sensor Windscreen Light Solar Condensation Unit is a practical, original comfort system component responsible for automatic control of wipers and lighting depending on road conditions. The used version allows you to reduce service costs while maintaining compatibility with factory BMW electronics. It is a good solution for users who expect predictable performance from assistance systems without the need to invest in a new part.