Audi A4 Climate Control Dead Due to Faulty Sensor

Had the exact same temperature control issue on my 2005 Audi A6 2.0T. The climate regulation system showed similar symptoms, complete HVAC failure and no response from controls. A faulty temperature sensor was indeed the root cause. The main sensor diagnostics revealed that the wiring harness connecting to the sensor had deteriorated, causing intermittent connections. The temperature sensor itself was actually fine, but the connector plug had corroded pins. This turned out to be a common issue with these models. The repair involved replacing the entire wiring harness assembly for the temperature control system rather than just the sensor itself. While not a complex repair, accessing the components required removing several dashboard pieces. The sensor replacement and rewiring took about 3 hours total. This was not a serious mechanical issue, but leaving it unfixed can prevent proper climate control and potentially strain other HVAC components over time. Regarding location, any certified Audi technician with diagnostic equipment should be able to handle this repair. The key is finding someone experienced with VAG climate control systems who can properly test the sensor connections before replacing parts.

Thanks for sharing your experience with the A6 climate control problems. Really helpful info about the wiring harness being the actual issue rather than the sensor itself. My A4 got fixed last month and your description matches exactly what I went through with the sensor diagnostics and HVAC system repairs. Would you mind sharing what you paid for the complete fix? The climate regulation work on mine was a bit costly but seems worth it since everything is working perfectly now. Did you notice any other issues pop up with the temperature control system since getting it repaired? Curious if I should watch out for anything specific in the coming months.

Just got around to seeing your update, glad you managed to get your A4 temperature control system sorted out! The repair on my A6 climate control turned out to be much simpler and cheaper than initially expected. After running comprehensive sensor diagnostics, the mechanic found it was just a faulty interior temperature sensor connection that needed fixing. The final bill came to 95 Euro, which covered fixing the cable and plug connection. Pretty reasonable compared to what I feared it might cost. The temperature control system has been working flawlessly since the repair, no issues whatsoever with the climate regulation. The HVAC response is actually better than it was even before the problem started. Its been about 8 months now, and the sensor replacement seems to have completely resolved the problem. Based on my experience, once the temperature sensor connection is properly fixed, you shouldnt encounter any further problems. Just keep an eye on the general performance of your climate control system during seasonal changes, but thats just good practice for any vehicle.

Thanks for the feedback. After reading about the wiring harness issues, I finally took my A4 to a certified independent shop last month. The sensor diagnostics confirmed a failed connection in the climate control wiring, just like others mentioned. The mechanic found corroded pins in the temperature sensor connector and had to replace the entire wiring assembly. The climate regulation system works perfectly now, proper cooling, accurate temperature control, and responsive HVAC operation. Total cost came to 280 Euro for parts and labor, which felt reasonable given the thorough diagnostic work and repair quality. Really glad I got this fixed before winter. The shop did great work and I would definitely recommend getting these sensor issues addressed by someone who knows these systems well. Much better than my previous mechanic experience and worth every cent to have proper climate control again.