Q5 Rain Sensor Wreaks Havoc on Multiple Systems

Having dealt with a similar sensor fault on my 2018 Audi Q3, I can share my experience as someone with moderate car expertise. The symptoms you describe match exactly what I encountered. The malfunctioning sensor was indeed causing multiple system failures. After inspection, the workshop found bubbles forming under the gel pad that connects the rain detection sensor to the windshield, causing erratic readings and system malfunctions. The repair involved: 1. Removing the old sensor unit 2. Cleaning the mounting area 3. Installing a new gel pad 4. Sensor calibration of the new unit 5. Testing all affected systems Total cost was 62 Euro including parts and labor. The fix resolved all issues immediately, auto wipers, light control, and other sensor-dependent systems started working perfectly again. To help further, could you share: Have you noticed any physical changes around the sensor area? Did these issues start gradually or all at once? Are there any visible marks or cloudiness near the sensor on the windshield? Have you had any recent windshield work done? This information would help determine if your issue matches the sensor fault I experienced.

Thanks for the detailed explanation of the sensor fault. Mine has 64253 KM and was serviced last month, but the issues persisted. I checked the area around the light sensor today and noticed some discoloration near the mounting point. All problems started suddenly after a rainy day. No recent windshield work has been done. The car electronics seem to go haywire especially during wet weather. Will take it to the shop this week based on your experience with the gel pad issue. The auto sensor problems match your description perfectly. Do you know if this is covered under the standard warranty?

Based on the issues you described and the discoloration you noticed, this definitely sounds like the same sensor fault I encountered. Since your Q3 is from 2020, this should absolutely be covered under the standard warranty, which typically runs for 4 years or 80000 KM for these sensor-related problems. The discoloration around the light sensor mounting point is a telltale sign of moisture intrusion. The fact that the car electronics act up particularly during wet weather further confirms my initial diagnosis. The gel pad deterioration tends to worsen with exposure to moisture and temperature changes. When I had mine fixed, the service department confirmed this was a known issue with the rain-light sensor in our model year. Make sure to mention the discoloration and the correlation with wet weather when you take it in. The sensor calibration process after replacement is critical, if not done properly, the automatic functions might still act erratically. Quick tip: while waiting for your service appointment, try to park in covered areas when possible. Excessive moisture exposure could accelerate the sensor deterioration even further.

Thank you so much for confirming my suspicions about the light sensor problems. Its great to hear this can be fixed under warranty since my car has only 64253 KM. Really appreciate you explaining your experience in detail, the discoloration I found matches what you described perfectly. Will definitely mention the moisture correlation and gel pad deterioration when I take it in. Planning to book the appointment tomorrow and will make sure they do the sensor calibration properly. Until then, I will park in my garage to prevent more moisture damage. Never realized these car components could be so sensitive to water exposure. Will update once the repair is done. Hoping for the same positive outcome you had with your sensor repair. Makes sense now why all these systems started acting up after that rainy day. Interesting how one small car electronics component can affect so many systems. At least now I know what to expect at the service appointment. Thanks again for helping me avoid an unnecessary diagnostic fee by sharing your experience.