VW Golf TDI Humidity Sensor Causing Multiple Failures

As someone with some experience working on VWs, I had a very similar issue with my 2017 VW Passat TDI last winter. The symptoms matched exactly what you describe, climate control acting up and various electrical gremlins tied to the automotive sensor system. After diagnostic testing, my workshop found that the humidity sensor wiring harness had partially corroded where it connects to the main plug. The connection issues were causing multiple systems to malfunction since the car sensor network relies on proper communication between components. The fix was relatively straightforward, they cleaned the connections and replaced the damaged section of the wiring harness. Total cost was 95€ for parts and labor. Since then, all systems have worked perfectly. Before jumping to conclusions about the humidity sensor itself being faulty, have the wiring connections checked first. Often these electrical issues stem from connection problems rather than sensor failure. To provide more specific guidance, could you share: Are there any other electrical symptoms? Which error codes are stored in the system? When did the issues first start appearing? Does the windshield fogging behavior seem normal? These details would help determine if your case matches what I experienced with the wiring harness issue.

Had my latest service at 76921km. The wiring connections were all inspected and in good condition. The issue persists despite cleaning the connectors. Our climate control module still shows fault codes and the electrical issues remain, especially with windshield fogging control. The workshop data suggests the humidity sensor itself is failing rather than just connection problems. Given the mileage and common failure patterns in this model, it seems like sensor replacement might be needed rather than just electrical fixes.

The symptoms you describe definitely point toward a faulty humidity sensor rather than wiring issues, especially since your connections checked out fine. After my initial wiring repair didnt solve the problem completely, I also ended up needing a full sensor replacement on my VW. When I replaced the humidity sensor at around 80000km, it resolved all the connected issues, the erratic climate control, windshield fogging problems, and those persistent fault codes in the system. The sensor calibration process was crucial, make sure your workshop performs this step after installation. The total repair cost was 280€ including the new sensor and calibration. While not cheap, it was worth fixing since these sensor issues can affect multiple vehicle systems and safety features. The dashboard warning lights cleared immediately after the repair. One tip: during sensor replacement, have them check the surrounding seals and gaskets. In my case, moisture intrusion had contributed to the sensor failure, so replacing the weatherstripping helped prevent future problems. Based on your mileage and symptoms matching my experience, going straight for sensor replacement seems like the right call. The electrical issues and climate control problems are classic signs of humidity sensor failure in these models.

Thanks for confirming this matches your experience with the humidity sensor replacement. Really helpful to know the calibration step is important, will make sure to mention that specifically at the workshop. The 280€ cost seems reasonable considering all the systems affected. Will book the repair next week. My main concern was spending money on replacing parts without being sure of the root cause, but the matching symptoms and similar mileage when your sensor failed makes me confident this is the right fix. The persistent electrical issues and climate control malfunctions line up exactly with what you described. Good tip about checking the seals too, makes sense that moisture could damage the sensor. Will have them inspect all the weatherstripping while they do the replacement. Hopefully this resolves all the issues like it did in your case.