S8 Sunlight Sensor Linked to Heating System Failure

Had similar issues on an Audi S7 2020 model. The fault detection system initially pointed to the sunlight sensor, but the actual problem was more complex. The car sensor wiring harness near the sunlight sensor had partially melted due to a manufacturing defect, causing intermittent heating system failures. The repair required complete replacement of the wiring harness and installation of a new automotive sensor unit. This was definitely a serious issue that needed immediate attention, as faulty wiring could potentially lead to more significant electrical problems. The sensor calibration alone would not have fixed the underlying problem. The wire insulation breakdown was causing false readings, making the heating system malfunction. After the harness replacement and proper sensor calibration, the heating system worked flawlessly. For S8 models, these symptoms often indicate a similar wiring issue rather than just a sensor problem. Would strongly recommend getting a professional diagnosis, as continuing to drive with compromised wiring could affect other systems. This type of repair requires specialized diagnostic equipment and expertise with Audi electrical systems, so choosing a qualified shop is crucial.

Thanks for sharing those details about the S7 wiring harness issue. Your symptoms match what I experienced exactly. Did the replacement and HVAC sensor calibration completely solve it for you? Been a few weeks since my dealer did the repairs and while the heating works better now, I still notice some inconsistency when the sun hits directly. The solar sensor seems a bit laggy responding to changes. Curious about the repair cost if you dont mind sharing. My regular shop quoted 2100 Euro for a complete fix including the harness replacement, which felt steep. Would help to know what others paid for similar work.

Got my S7 fixed last month and the solar sensor issue is completely resolved now. The initial symptoms were exactly as you described, but it turned out much simpler than expected. The mechanic found a loose connection at the daylight sensor plug, which was causing those inconsistent heating responses. No need for a complete harness replacement in my case. The temperature sensor and HVAC systems now respond instantly to sunlight changes after they fixed the faulty connection. The total bill came to 95 Euro for diagnosing and securing the sensor fault. Much better than the 2100 Euro quote you received. If your system still shows lag when responding to direct sunlight, the car sensor might need recalibration. Sometimes the solar sensor needs a proper reset after connection repairs. Worth having the shop check if the calibration was done correctly, especially since youre still experiencing delayed responses. Based on my experience, I would get a second opinion before agreeing to a full harness replacement. A loose connection or simple sensor fault can mimic more serious issues.

After that helpful advice about checking sensor connections, I decided to try a different shop. Took it to a certified Audi specialist who actually found the exact same issue, just a loose connection at the solar sensor plug. They fixed it within an hour and did a proper temperature sensor calibration. Total cost was only 120 Euro for diagnostic and repair work. Such a relief compared to the 2100 Euro quote from the other place! The fault detection system now shows no errors, and the heating responds perfectly even in direct sunlight. Really glad I got that second opinion instead of rushing into the expensive harness replacement. The automotive sensor is working exactly as it should now. Sometimes the simpler fix is the right one.