Dead AC System in Audi Q5 Needs Urgent Diagnosis

As an Audi A4 2020 diesel owner, I encountered nearly identical AC issues last season. After proper AC diagnostics, the problem was traced to a failed AC relay and a faulty control valve in the compressor system. The temperature control unit would not respond, similar to your symptoms. The complete system shutdown you describe often points to electrical issues rather than a simple refrigerant leak. The fact that the AC wont activate when pressing the button suggests its likely an electrical fault in the control circuit or a failed relay, rather than a blower motor problem. The repair required replacing the AC relay, control valve, and performing a full AC maintenance check. This was definitely a serious issue that needed immediate attention to prevent compressor damage. These valve issues are known weak points in VAG climate control systems. Before heading to a shop, check your fuses first, its a simple first step in AC diagnostics. If theres unusual AC noise from previous days before the complete failure, make sure to mention this to your technician as it helps narrow down the diagnosis. These symptoms typically require professional diagnostic equipment to properly identify the root cause, as multiple components can trigger similar failure patterns.

Thanks for your detailed feedback on my AC issue. After reading about your experience, Im even more convinced our problems might be identical, especially since both issues involve complete system shutdown. The relay and control valve theory makes a lot of sense. Could you share how much the repair ended up costing? Also wondering if youve had any AC efficiency issues since the fix? My biggest concern is getting it fixed properly the first time to avoid repeat visits. Ive already checked the fuses as suggested and they all seem fine. The AC pressure switch might be worth looking at too from what Ive read.

Following up on your questions, my AC maintenance was successful and completely resolved the problem. The repair cost was 1000 Euro, covering the replacement of defective valves in the air conditioning system. The AC diagnostics revealed similar issues to what you described. After the repair, the AC efficiency returned to normal with perfect temperature control, no recurring problems in over a year. The blower motor works flawlessly, and the cold air distribution is consistent throughout all vents. The AC pressure switch check was smart thinking, but in our case, the valves were definitely the culprit. Having proper AC diagnostics done by a qualified technician proved essential for identifying the exact issue and fixing it right the first time. The investment was worth it for reliable climate control, especially since these valve problems can lead to more expensive compressor damage if left unaddressed. Since the repair, the system maintains optimal AC efficiency in all operating conditions.

Thanks everyone for the helpful insights. I took my Q5 to a certified shop after all your feedback. The pressure switch and relay were both functioning properly, but just like mentioned, it turned out to be a faulty control valve. The repair cost came to 950 Euro including parts and labor. They also performed a full AC maintenance check which showed everything else was in good condition. The blower motor and temperature control are now working perfectly. Really glad I got this checked quickly, the technician mentioned waiting longer could have led to compressor damage. The AC has been running great for the past two weeks with consistent cold air flow. Looking back, the electrical issue diagnosis was spot on. Having this knowledge beforehand helped me communicate better with the shop and understand the repair process.