VW Transporter Heat & Sensor Fault, DIY Fix Guide

Had a similar fault detection issue on my 2015 VW Golf GTI. The daylight sensor malfunction initially appeared as a climate control problem, creating inconsistent heating patterns. The diagnostic revealed a damaged wiring harness connector near the sensor housing. The sunlight sensor connects to multiple systems including climate control, and when the signal gets compromised, it can affect temperature regulation. In my case, the fault was traced to corroded pins in the main connector plug, not the car sensor itself. The repair involved cleaning the connector terminals and replacing the wiring harness section where moisture had caused the corrosion. This was actually a serious issue since leaving it unfixed could have led to more extensive electrical problems across multiple systems. A sensor fault like this often gets misdiagnosed as a climate control module issue, which leads to unnecessary parts replacement. Would recommend having the wiring and connections checked first before replacing any components. The stored error code should point to the specific circuit that needs inspection.

Thanks for sharing your experience with the sensor fault. Those connector issues can be really tricky to diagnose. Just dealt with the repair last week and wondering what the final cost was in your case? My VW is going back to the shop soon for a sensor calibration check, so it would help to have a rough estimate. Have you experienced any other issues since the harness repair?

Actually took my VW to the shop last month for this exact sunlight sensor problem. Total cost came to 95€ for fixing the faulty cable connection, which was considerably less than initially expected. The HVAC sensor is now working perfectly, and the climate control responds correctly to changing conditions. Since the repair, all the sensor-related issues have completely cleared up. No more error codes or heating inconsistencies. The solar sensor now properly communicates with the climate system, which makes a noticeable difference in cabin comfort. Really glad I had them check the connections first instead of replacing the entire unit. A proper sensor calibration is definitely worth doing after any repairs to these components. Just make sure they verify all connections are secure and moisture-free to prevent future issues. The original fault hasnt returned since the fix, so it seems the connector was indeed the root cause.

Finally got the car back from the shop yesterday. Turned out my issue was similar but slightly different. The mechanic found moisture damage in the sunlight sensor housing itself, not just the connector. Total repair came to 180€ including sensor calibration and replacement of the damaged part. The car sensor readings are now accurate and the heat works perfectly. No more fault codes showing up on the dash. The technician also sealed the housing better to prevent future moisture issues. Pretty relieved it wasnt a more complex HVAC sensor problem or something wrong with the entire climate control system. Glad I asked here first since it helped me understand what to expect at the shop. The repair was straightforward once they knew where to look. Driving home with properly working heat made it worth every cent.