Rain Sensor BMW F20 F21 F30 F31 Windscreen Light Solar Condensation Unit 7939168

Rain Sensor BMW F20 F21 F30 F31 Windscreen Light Solar Condensation Unit is a precision component from the Electronic control modules and controllers group, responsible for the automatic reaction of wipers to precipitation on the windscreen. A properly selected sensor ensures stable system operation, improves driving comfort, and allows for full utilization of the vehicle's equipment features. By using an original BMW solution, proper communication with the electrical installation and body systems is maintained.

Specifications and technical data

• SKU: 7939168
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7939168
• Substitutable numbers: 7939168, 61357939168, 9475146, 61359475146, 6823540, 61356823540, 9496241, 61359496241, 6806740, 61356806740, 9397908, 61359397908, 9861557, 61359861557, 6801263, 61356801263, 6819589, 61356819589, 9388380, 61359388380
• Location on the vehicle: Front
• Category: ECUs & Computer Modules

Function and role of the rain sensor in BMW

The rain sensor mounted in the windscreen area is responsible for analyzing the amount of water on the glass and sending a signal to control the wipers. A properly functioning module enables automatic adjustment of the wiper frequency to the intensity of precipitation, which translates into better visibility and safer driving in changing weather conditions. In BMW F20, F21, F30, and F31 series vehicles, such a sensor works with the vehicle's electronic system, utilizing the manufacturer's dedicated algorithms.

Construction and integration with vehicle electronics

The presented module belongs to the Electronic control modules and controllers group, meaning it is designed to work within the vehicle's controller network. Its placement on the vehicle in the front area allows for direct reading of conditions on the windscreen and rapid transmission of information to the wiper system. The sensor's construction is prepared for compatibility with the factory mount and wiring harness, which facilitates installation and reduces the risk of communication errors in the vehicle's bus.

Selection by part numbers and compatibility

For this type of component, correct selection based on the part number and interchangeable numbers is crucial to ensure full compatibility with a specific BMW equipment version and model year. The rain sensor module is linked to the body controller software, which is why matching it according to the manufacturer's technical data minimizes the risk of errors, dashboard messages, or improper wiper operation. In case of doubt, it is worth comparing the markings with the currently installed component or using verification via the VIN number.

Condition, installation, and service application

The offered sensor is a used part, which in service practice allows for an economical replacement of a damaged module while maintaining the original BMW specification. Installation in the windscreen area requires keeping the glass surface clean and properly seating the sensor in the holder to ensure accurate reading of external conditions. This type of solution is often chosen by workshops specializing in the BMW brand that prioritize proven components while maintaining the factory logic of comfort and safety systems.

More about BMW electronics and safe part selection

If you are planning a comprehensive repair or upgrade of the body electronics area in your BMW and need other elements from the same group, such as comfort modules, light controllers, or other body controllers, check the available parts in the BMW electronic control modules and controllers category.

To better understand how to consciously choose used modules and sensors, including rain sensors, it is worth reading the guide on selecting electronics by OEM numbers and software compatibility: Used automotive electronics on board – why is it worth choosing second-hand ECU modules and sensors?.

For drivers and workshops who want to further organize the online parts purchasing process, a practical guide describing step-by-step how to safely verify offers and technical parameters will also be helpful: Safe purchase of used car parts online – a step-by-step guide.