1. Sensor: The rain sensor is typically located on the windshield of the vehicle. It consists of a small optical device equipped with an infrared (IR) emitter and a receiver.
2. IR Emitter: The IR emitter emits infrared light towards the windshield.
3. Detection: When raindrops fall onto the windshield, they disrupt the path of the IR light emitted by the sensor. Some light is absorbed or refracted by the water droplets.
4. Receiver: The receiver in the rain sensor detects the change in the IR light caused by the raindrops. As rain intensity increases, more IR light is blocked or deflected.
5. Signal Processing: The sensor converts the detected changes in IR light into an electrical signal. This signal is then processed by the electronic control unit (ECU) of the vehicle.
6. ECU Response: Based on the processed signal, the ECU triggers various actions depending on the vehicle's settings and features:
- Wiper Activation: The ECU may automatically initiate the intermittent wiping function of the windshield wipers.
- Wiper Speed Adjustment: The ECU can adjust the speed of the windshield wipers based on the intensity of rainfall.
- Headlight Activation: In some cases, the rain sensor can also trigger the automatic activation of headlights when it detects heavy rainfall or poor visibility.
- Dashboard Alert: Certain Volkswagen models might display a visual or auditory alert on the dashboard to indicate the detection of rain.
It's worth noting that the sensitivity of rain sensors can be customizable in some Volkswagen vehicles. This allows drivers to adjust the level of responsiveness to rain and fine-tune the automatic wiper activation based on their preferences.
