VW Touran HVAC Fault: Solar Sensor Mystery

I had a similar issue with my 2017 VW Tiguan diesel last winter. As someone with some hands-on experience maintaining VWs, I recognized the symptoms right away. The daylight sensor and HVAC sensor system problems can be tricky to diagnose. My car showed similar behavior, inconsistent heating output and temperature regulation issues. The sunlight sensor was actually working fine, but the problem was traced to a faulty connection in the wiring harness leading to the automotive sensor cluster. The workshop ran a full diagnostic scan and found error codes related to the HVAC control module. They discovered a damaged wire connection near the sensor assembly. The repair involved replacing the wiring connector and testing all sensor functions. Total cost was 95€ including diagnostic work. To help diagnose your specific case, could you share: Are the heating issues constant or do they vary with outside temperature? Does the climate control display show any error messages? Have you noticed if the auto temperature control works worse in direct sunlight? Which exact error code is stored in the system? This would help determine if your issue matches what I experienced with my Tiguan and provide more targeted advice.

I took my car in last week for diagnostics at 119801km. The workshop confirmed it was indeed a fault with the HVAC sensor cluster. They found multiple error codes pointing to the sunlight sensor connection being compromised. The fault detection system showed the sensor was getting incorrect readings, causing the heating system to malfunction. A complete sensor replacement was needed as the wiring repair alone didnt solve the issue. After replacing the defective car sensor unit, the heating works perfectly again and maintains consistent temperature. The total repair cost was 320€ including parts and labor. The mechanic recommended checking sensor functions during yearly service to catch potential issues early. Would definitely suggest getting it checked soon, as these sensor faults can affect both comfort and fuel efficiency.

The sensor replacement was definitely the right call for your Touran. My Tiguan actually ended up needing a similar repair a few months after the initial wiring fix I mentioned. The temporary wiring repair I tried first only worked for about 2 months before the heating issues returned. The fault detection system kept showing intermittent sensor errors. When I went back to the workshop, they performed a complete sensor calibration but ultimately recommended replacing the entire automotive sensor unit, just like in your case. The complete sensor replacement solved all issues permanently. My repair cost was slightly higher at 395€ since they had to do extra diagnostic work from the failed first attempt. Looking back, I should have gone for the full sensor replacement right away instead of trying the cheaper wiring fix. Good call on the regular sensor checkups during service. Since the repair, I make sure the workshop specifically tests all HVAC and daylight sensor functions during maintenance. Helps catch any developing issues before they cause system failures.

Thanks for sharing those details about your repair experience. My sunlight sensor and HVAC issues turned out quite similar to yours. After comparing repair costs, I feel better about what I paid, seems to be in the normal range for this type of sensor work. The fault detection system on my Touran is now working flawlessly after the sensor replacement. The consistent temperature control makes such a difference in daily driving. Really glad I didnt try going the cheaper route with just a wiring fix like you initially did. Following your experience, I will definitely have the workshop do thorough sensor calibration checks during future services. The automotive sensor cluster is clearly a critical component that needs regular monitoring. 320€ was worth spending to fix it properly the first time and avoid repeated workshop visits. Good to know these sensor issues are relatively common and have a clear fix. Having a reputable workshop properly diagnose and replace the faulty components seems to be the key to resolving HVAC control problems permanently.