Audi Q7 Hybrid HVAC Blower Failure & Sensor Issues

Had a similar situation with my 2017 Audi Q8 Hybrid. The climate control system showed identical symptoms, complete blower failure combined with erratic auto recirculation behavior. The root cause turned out to be a faulty AUC sensor wiring harness where the connector had corroded. The air quality sensor connections were also affected, causing the automatic climate control system to malfunction. Initial diagnosis pointed to a complete sensor replacement, but the actual fix required: Cleaning the connector pins, Replacing the wiring harness section, Recalibrating the air quality sensor, Resetting the climate control module This was definitely a serious issue since the entire climate control system was compromised. The repair prevented potential damage to other HVAC components that could have failed due to improper system operation. The connector deterioration is a known weak point in these models. Suggest having a qualified technician check the wiring harness and sensor fault codes before replacing any major components.

Thanks for sharing that fix info. Really glad to hear the climate control system could be repaired without a complete sensor replacement. My Q7 is at the shop now and they mentioned similar issues with the cabin air sensor and wiring. How much did the repair end up costing you? Also wondering if youve had any other HVAC sensor problems since getting it fixed?

Thanks for asking about the follow-up. Just got my Q7 back from the shop and can confirm the AUC sensor fault has been completely resolved. The auto recirculation is now working perfectly again. The total repair cost was 95 Euro which covered fixing the faulty cable connection to the air quality sensor. This was much better than having to replace the entire sensor unit. Since the repair 6 months ago, the climate control system has been running flawlessly. No more sensor faults or issues with the auto recirculation function. The air conditioning sensor readings are all normal now. The mechanic mentioned this is a common issue that often just needs a connection fix rather than full component replacement. Regular checks of the sensor connections can help prevent similar problems in the future. For reference, my cabin air quality readings have been stable and accurate through all weather conditions since the repair.

Just got back from the mechanic today, such a relief! After reading about your similar experience, I showed them your repair solution. They found the same issue with corroded connectors affecting the air quality sensor. Fixed the wiring connection and cleaned the HVAC sensor assembly for 120 Euro total. Much cheaper than the 450 Euro they initially quoted for a full sensor replacement. The auto recirculation and blower are working perfectly now. The cabin air sensor readings are back to normal too. Really appreciate you sharing your experience, saved me both time and money by pointing the mechanics in the right direction from the start. Will definitely keep an eye on those connections from now on to catch any early signs of corrosion. Thanks again for the helpful advice!