Ford Focus Mk2 Front Window Windscreen Rain Light Sensor Unit 3S7T-17D547-AA

Ford Focus Mk2 Front Window Windscreen Rain Light Sensor Unit is a component from the Electronic control modules and controllers group, responsible for the automatic operation of wipers and lights depending on road conditions. Mounted in the windshield area, the sensor enhances driving comfort, improves ergonomics, and allows the driver to focus on operating the vehicle.

Specifications and technical data

• SKU: 3S7T-17D547-AB
• Mark: Ford
• Condition: Used
• OEM Part Number: 3S7T-17D547-AB
• Substitutable numbers: 3S7T-17D547-AB, 3S7T17D547AB, 1745368, 3S7T-17D547-AC, 3S7T17D547AC
• Location on the vehicle: Front
• Category: ECUs & Computer Modules

Purpose and function of the sensor

The presented rain and light sensor is designed to operate in the front part of the vehicle, where it monitors precipitation intensity and lighting conditions. Based on the readings, it transmits signals to the appropriate controllers, which enables:

• automatic activation and adjustment of wiper operation,
• automatic switching on of lights when visibility deteriorates,
• stable cooperation with factory comfort and safety systems.

Thanks to this solution, the driver gains more predictable vehicle behavior in changing weather conditions and reduces the need for manual switch operation.

Benefits of using an original Ford module

As a Ford brand component, the sensor is structurally matched to the electrical installation and electronic system architecture of the Ford Focus Mk2. This means:

• proper communication with other control modules,
• appropriate scaling of rain and light sensor sensitivity,
• preservation of factory comfort functions without the need for additional modifications.

The product comes from the Electronic control modules and controllers segment, which emphasizes its role as an integral part of the vehicle's electronic system, rather than a universal replacement.

Vehicle placement and installation aspects

The sensor is designed for installation in the windshield area, in the zone of the rearview mirror and cowl equipment. Such placement ensures optimal measurement conditions for both the amount of external light and the presence of water on the glass. When replacing, it is important to:

• maintain the correct position relative to the glass surface,
• ensure proper connection to the vehicle's electrical harness,
• verify correct operation in automatic mode after installation.

The condition described as used means that the item comes from disassembly and is intended for further use after proper installation and verification of operation in the vehicle.

Why consider used electronics

In the case of components such as rain and light sensors, choosing a used original module can be a technically justified alternative to new parts. This allows for maintaining consistency with the vehicle's factory configuration while reducing repair or upgrade costs. If you want to better understand when used automotive electronics are a good choice and how to safely select comfort modules or sensors, check out the article: Second life of electronics – when is it worth choosing used controllers and sensors.

If you are planning a comprehensive repair or upgrade of the windshield area and comfort system in your Ford and need other elements from the same group, such as control modules, comfort controllers, or additional sensors, check the available parts in the Ford electronic control modules and controllers category.