VW Fox Climate Control Failure, Multiple Sensors Dead

Had the same climate control problems on my 2002 VW Polo TDI. The electrical issue turned out to be a faulty connection at the humidity sensor which controls both the AC and windshield fogging functions. The mirror heating and washer nozzle problems were related since they share the same wiring harness in that area. The sensor calibration was impossible because the main connector had corroded due to water ingress near the windshield. The automotive sensor cluster needed to be removed, connectors cleaned, and wiring harness sealed properly. While not a complex repair, it requires specific diagnostic equipment to reset the climate control module after fixing the connections. The symptoms matched exactly, unusual AC cutoffs, no response from auto-defog, and auxiliary heating functions stopped working. Getting to the wiring meant partial dashboard removal, so while the parts cost was reasonable, labor time made it a serious repair job. Key checks before garage visit: Check fuses related to climate control, Look for visible water damage near windshield edges, Test if the issue appears worse in humid conditions, Document when functions fail (all at once or gradually) The repair requires proper diagnostic tools, so DIY options are limited. Would recommend having a certified shop handle the sensor and wiring repairs to avoid future electrical problems.

Thanks for sharing the details about the sensor and wiring harness problems. My VW Fox had almost identical climate control issues last winter. I took it to the shop based on your description and they confirmed the humidity sensor malfunction along with corroded connections. Just wondering, how much did the complete fix end up costing you? And has everything worked properly since the repair? I want to make sure I budget correctly and avoid any recurring electrical issues with the climate system.

The repair sorted out all my climate control problems completely. Since fixing the humidity sensor connections six months ago, I have not experienced any more windshield fogging issues or dashboard warning lights. The total cost came to 95€ for repairing the defective cable connection and cleaning the corroded plugs. The visibility in all weather conditions is now perfect, and the automotive sensor functions exactly as it should. The mirror heating and washer nozzles work normally again, even during freezing temperatures. The repair cost was actually lower than expected since the sensor itself was fine, it was just the wiring connection causing all the trouble. If your symptoms match mine, you are likely looking at a similar repair cost, assuming no additional components need replacement. The key was having a technician who knew exactly where to look for these specific VW climate control electrical issues.

Thanks for the advice. I finally got it fixed last week. The mechanic found exactly what was described, corroded connections at the humidity sensor. The visibility is great now and all climate control functions work perfectly. The total repair came to 120€, slightly more than expected because they had to replace a small section of the wiring harness that was too damaged to repair. The sensor calibration took about an hour since they needed special equipment to reset the climate control module. Really glad I went prepared with the specific electrical issue details. Saved time on diagnostics and helped avoid unnecessary parts replacement. All climate features are working great now, no more frozen washer nozzles or fogged windshield issues. Worth every cent to have proper heating and AC function again.