Audi Q2's Failed Heating Traced to Sunlight Sensor Issue

I encountered a similar heating issue on my 2020 Audi Q3 35 TFSI. Initially, the system showed irregular temperature readings and poor cabin heating. The problem was traced to a faulty solar sensor connection, which affected the climate control system calculations. The automotive sensor system in modern Audis relies heavily on the sunlight sensor input to regulate heating. When the cable connections degrade or get loose, the climate control unit receives incorrect data. In my case, the solar sensor itself was functioning, but the wiring harness needed replacement due to wear. The repair involved testing the sensor circuit, replacing the damaged wiring section, and recalibrating the climate control module. While not a major mechanical issue, proper diagnosis was crucial as misdiagnosis could lead to unnecessary part replacements. The car sensor network is quite complex in newer Audi models. A certified diagnostic tool can pinpoint whether its a sensor fault or connection issue. This helps avoid the common mistake of replacing the entire sensor unit when only the wiring needs attention. The repair was straightforward once correctly diagnosed, and the heating system has worked flawlessly since. Would recommend getting a proper diagnostic scan before any parts replacement.

Thanks for sharing your experience. That matches what happened to my Q2 exactly. After initially suspecting a faulty daylight sensor, the fault detection system showed it was actually just corroded wiring causing sensor calibration issues. Getting the wiring fixed solved the heating problems completely. How much did the repair cost you? And has everything stayed working properly since the fix? In my case the mechanics found some related moisture damage while doing the repair that needed addressing too.

Happy to report my repair costs were reasonable at 95 Euro for fixing the cable connection to the solar sensor. The HVAC sensor system has worked perfectly since the repair, with no recurring issues over the past months. The climate control maintains consistent temperatures now, unlike before when readings were erratic. The key was having a technician who properly diagnosed the faulty connection rather than rushing to replace the entire daylight sensor unit. Often these automotive sensor problems stem from connection issues rather than the components themselves being defective. Just make sure they thoroughly check for moisture-related damage like you mentioned, as water intrusion can cause similar problems to resurface if not addressed properly during the repair.

The visit to the mechanic turned out well in the end. After getting multiple opinions, I found a shop that took the time to properly diagnose the temperature sensor issue. They discovered corroded wiring near the sunlight sensor was causing the erratic HVAC sensor readings. Total repair cost was 180 Euro including fixing some moisture damage they found during inspection. The car sensor diagnostics showed it wasnt actually a faulty sensor unit like I initially thought. They replaced the damaged wiring harness and recalibrated the system. The heating has worked perfectly for the past 3 months with no sensor fault codes appearing since. Definitely worth getting a proper diagnosis rather than just throwing parts at the problem. The thorough inspection saved me from unnecessarily replacing the entire sensor assembly. Really glad I asked here first before letting the other shop replace parts that werent actually broken.