VW Scirocco's Sun Sensor Linked to Heating Issues

Having worked on my 2006 VW Golf TDI, I encountered a similar solar sensor issue last winter. With some experience in basic car maintenance, I recognized the heating problems were likely connected to the sunlight sensor malfunction. The symptoms matched exactly what you describe, inconsistent heat output and persistent fault codes. My temperature sensor readings were unreliable, causing the climate control system to behave erratically. After inspection, the workshop found a damaged wire connection to the solar sensor. The sensor calibration itself was fine, but the faulty connection was causing incorrect readings. The repair involved fixing the cable connection and clearing the sensor fault codes. Total cost was 95€ for diagnostics and repair. Before suggesting specific solutions for your Scirocco, could you share: The exact fault codes stored in memory, Whether the climate control shows any error messages, If the issues started suddenly or developed gradually, The location of the sensor fault (dashboard or elsewhere) This information would help determine if your issue matches the common sensor connection problems seen in this VW series.

Latest service completed at 146000km. Thanks for the detailed response. The fault code scanner shows P0513 and P0571. The climate control displays generic sensor fault warnings that come and go. The daylight sensor issues started gradually over the past month, but the heating problems appeared suddenly last week. The fault detection system points to the dashboard area, where the sunlight sensor is integrated into the auto-dimming mirror assembly. Looking at the service history, the sensor has never been replaced since manufacture. Based on your experience, it sounds like I might be dealing with a similar wiring issue. Do you think I should start by checking the connections before replacing the entire sensor unit? The dealer quoted 380€ for a complete sensor replacement, which seems steep if its just a wiring problem.

Thanks for providing those additional details. Looking at your description, your symptoms are indeed very similar to what I experienced with my Golf TDI. Given the cost difference between checking connections and full sensor replacement, I definitely recommend starting with a wiring inspection. In my case, the HVAC sensor issues also triggered multiple fault codes, but the root cause was just corroded wiring near the mirror assembly. The P0513 and P0571 codes combined with the intermittent temperature sensor warnings match the pattern I saw before my repair. When my fault detection system first highlighted the dashboard area, I was also quoted a full sensor replacement, but the actual fix was much simpler. A few specific points based on my experience: The gradual onset of sensor fault warnings often indicates wiring degradation rather than complete sensor failure, The sudden heating issues combined with existing sensor problems typically point to connection issues, 380€ for a complete unit replacement is actually higher than what I was quoted Consider having a workshop inspect the wiring harness first. My repair cost of 95€ included fault code clearing and basic diagnostics. Even if they spend an hour or two tracing the connections, you would still save significantly compared to replacing the entire sensor unit.

Thanks for the input. After reviewing the responses and comparing the symptoms, I feel more confident about how to proceed with my Scirocco's issues. I will book an appointment with my local workshop to inspect the wiring connections first, rather than jumping straight to replacing the entire solar sensor unit. The similarity between the fault detection patterns and the gradual onset of sensor issues makes me think the wiring could be the culprit, just like in the Golf TDI case. The fact that both the HVAC sensor and temperature sensor readings are affected strengthens the theory about wiring being the root cause. Even if the inspection reveals more extensive problems, starting with the wiring check could save me a significant amount compared to the 380€ dealer quote for full sensor replacement. Will update once I have the workshop findings. Really appreciate the detailed breakdown of the repair process and costs shared here. Makes me feel better about not rushing into the more expensive repair option.