Audi Q7 AC Dead: Common Relay and Refrigerant Issues

Having experienced a very similar AC efficiency issue with my 2013 Audi Q5, I can share some insights based on moderate experience with AC maintenance problems. The symptoms match exactly what happened to my car last summer. After running AC diagnostics, the workshop found defective valves in the air conditioning system. The temperature control was completely compromised, making the AC non-functional. The repair involved: Full system pressure test, Replacement of faulty expansion valves, Recharge of refrigerant, AC system vacuum test, Final performance check Total cost came to 1000 Euro including parts and labor. The repair restored proper AC performance and eliminated the intermittent operation issues. For more accurate diagnosis of your Q7, could you provide: Any unusual AC noise before complete failure? Does the compressor clutch engage when you turn on AC? Are there any error codes showing? When was the last AC maintenance service done? This information would help determine if you are facing the same valve-related problem or potentially something different.

I have the same car model with 15959 KM on the odometer and got my AC fixed last month. The pressure switch was indeed the culprit in my case. The blower motor and compressor were fine, but the system would not engage properly due to the faulty switch. The repair included replacing the pressure switch and recharging the refrigerant, coming to about 450 Euro total. After the fix, the AC efficiency returned to normal with consistent cooling. What helped diagnose the issue quickly was that my system showed similar symptoms, complete shutdown followed by occasional operation. I would suggest getting the pressure sensors checked first before looking into more expensive components.

Thanks for sharing your repair experience. Your pressure switch diagnosis matches another repair pattern we are seeing on these Q7 models. The AC diagnostics definitely pointed to the control system rather than mechanical failures in my case too. The cooling system problems seem to show consistent symptoms across Q7s from this generation: intermittent operation followed by complete failure. After my expansion valve repair, I also had the pressure switches inspected and replaced preventively since accessing them was straightforward during the service. For others reading who face similar AC maintenance issues: the repair sequence typically involves: 1. System pressure testing 2. Control module scan for fault codes 3. Checking pressure switch operation 4. Inspecting refrigerant levels 5. Testing temperature control function My total repair ended up more expensive since I needed the expansion valves, but the pressure switch replacement alone is a much more economical fix when that is the sole issue. Good call on identifying the specific component rather than doing a complete system overhaul. Would be interested to hear if you notice any AC noise now that the system is running properly again? Mine has been whisper quiet since the repair.

Thank you for sharing all those details about the expansion valve repair. Yes, after fixing the pressure switch, my AC now runs completely silent with no unusual AC noise at all. The blower motor works smoothly and the cooling system maintains consistent temperature. I should mention I had my AC maintenance done at the 15000 KM service interval, which probably helped catch this issue before it caused damage to other components. The diagnostic process was straightforward since the pressure switch failure symptoms were quite distinct from compressor or refrigerant problems. For others with similar issues, my repair receipt shows the parts and labor breakdown: Pressure switch replacement: 180 Euro, Refrigerant recharge: 120 Euro, Diagnostic testing: 100 Euro, Labor: 50 Euro The cooling performance has been perfect for the past month, making me glad I addressed the issue promptly rather than risking damage to more expensive components.