Audi S5 Climate Control Failure, Sensor Diagnosis Needed

Coming from a similar experience with a 2010 Audi S4 with the 3.0L engine, this sounds exactly like the HVAC sensor failure I encountered. The temperature control system completely stopped responding, affecting both the climate regulation and AC operation. The root cause was a faulty temperature sensor connection near the evaporator housing. The main temperature reading component was fine, but the wiring harness had deteriorated where it connected to the sensor. The temperature control module wasnt receiving proper signals, causing the system to default to a non-operational state. The repair process involved: Diagnostic scan to confirm the temperature sensor circuit fault, Removal of lower dash components to access the wiring, Replacement of the damaged wiring harness section, Testing the temperature sensor connectivity, Full system calibration This was a significant repair requiring specialized knowledge of Audi HVAC systems. While not the most expensive fix, it needed proper diagnostic equipment and expertise. Most importantly, having it fixed properly prevented potential damage to other climate control components. Would strongly recommend getting that error code read first, as it will point directly to which part of the temperature control system is failing.

Thanks for the detailed explanation of your S4 sensor replacement experience. Currently dealing with the same temperature control issues in my S5, and your description matches my symptoms exactly. Good to know about the wiring harness being a potential culprit rather than just the sensor itself. Before I schedule a repair, could you share how much the total fix cost you? Also wondering if youve had any recurring temperature sensor issues since the repair was done? Want to make sure Im prepared for both the immediate fix and any potential follow-up problems with the HVAC system.

After having the repair done by a certified mechanic, I can report the HVAC system is working flawlessly. The interior temperature sensor diagnostics revealed exactly what we suspected, a faulty connection was preventing proper temperature readings. The total repair came to 95 Euro, which covered fixing the cable and plug connection. This was actually less expensive than I initially expected, especially since the temperature sensor itself was functioning correctly. The issue was isolated to the wiring connection point. Its been 8 months since the repair, and Ive had zero recurring climate issues. The temperature control system maintains perfect readings and the auto climate function works as intended. The AC performance is back to normal as well. This experience reinforces how important proper sensor diagnostics are, what seemed like a potentially major HVAC system failure was ultimately just a connection issue. Having a skilled technician who understood the Audi climate control system made all the difference.

Thanks for the input. I finally got my S5 fixed last week. My initial concern about the climate regulation system turned out to be spot on. The mechanic I found specializes in temperature sensor diagnostics and immediately identified the issue through proper testing. Like others mentioned, it was indeed a wiring connection problem affecting the temperature control system. The repair took about 3 hours. They had to remove some dash components to access the wiring, but the actual fix was straightforward. Total cost came to 120 Euro, which included the diagnostic scan and labor. They also checked the entire climate control system to ensure no other components were affected. Been driving for a week now and the HVAC is working perfectly. The auto temperature settings are responsive again and the AC blows cold. Really glad I got a second opinion and found a shop that knew exactly what they were dealing with. Definitely learned my lesson about getting proper diagnostics done first rather than assuming the worst. Thanks again for pointing me in the right direction with this sensor issue.