VW Eos Blower Motor Failure: Sensor Issues Explained

Had this exact issue on a 2010 VW Passat 2.0 TDI. The climate control system failure started with intermittent blower operation before completely stopping. Initial diagnosis pointed to the AUC sensor, but after testing it turned out to be corroded wiring connections at the blower motor resistor. The air quality sensor and auto recirculation were working fine, which helped narrow down the problem. Common failure points in these VW blower systems include: 1. Blown blower motor fuse 2. Failed blower motor resistor 3. Corroded wire connections 4. Faulty blower motor 5. Climate control module issues Best troubleshooting steps: Check fuse first, Listen for motor humming when speeds change, Test voltage at the connector, Inspect wire harness for obvious damage This was a moderate repair job requiring removal of the lower dash panel and blower assembly. The repair involved replacing the corroded connectors and installing a new wire harness section. While not extremely serious, leaving it unfixed can affect window defrosting and overall cabin comfort. Getting proper diagnosis is crucial, the air conditioning sensor system is complex and problems can be misdiagnosed as sensor faults when wiring is the real culprit.

Thanks for that detailed reply. I had almost identical symptoms on my VW Eos last winter. The blower motor resistor and wiring harness replacement fixed it for me too. Just wondering, what did the repair end up costing you? And have you noticed any other HVAC or cabin air sensor related issues since the fix? Mine has been running fine, but I want to be prepared if this type of problem tends to come back.

Glad the fixes worked out for you too. My total repair cost was 95€ for the faulty cable and plug connection work. The mechanic found and resolved the AUC sensor fault during the same visit, which was just a connection issue needing cleaning and reseating, no replacement parts needed there. The HVAC system has been working flawlessly for over a year now. The auto recirculation and climate control functions are all operating normally. No sensor issues or blower motor problems have returned. The key was getting a proper diagnosis and repair of those corroded connections rather than just replacing parts. Regular inspection of the wire harness connections during routine maintenance helps prevent these kinds of failures from recurring. The VW climate control system is quite reliable once the wiring issues are properly addressed.

Thanks everyone for your insights. I finally got this resolved last week. After getting recommendations here, I took it to a different mechanic who actually specializes in VW electrical systems. The final bill came to 120€ for parts and labor, more reasonable than I expected. They found exactly what was described, corroded wiring at the blower motor connection. Fixed the wiring harness and cleaned up all the cabin air sensor connections while they were in there. The whole climate control system is working perfectly now, both the blower and the auto recirculation. Much better experience than my previous mechanic who wanted to replace the entire blower motor assembly without even checking the wiring. Really glad I asked here first before going that route. The new shop even showed me what to watch out for in case similar issues develop in the future. Much more professional approach all around.