VW Lupo HVAC System Dies, Complete AC Failure

I had a similar issue with my 2005 VW Polo diesel. As someone with moderate experience in car maintenance, I initially thought it was the AC compressor too, but after taking it to a workshop specializing in auto AC repair, the diagnosis revealed a faulty air conditioning control unit. The symptoms matched yours exactly, complete system failure, warning lights, and the car air conditioning stopped responding altogether. The cooling system diagnosis showed multiple error codes, pointing to the control module rather than mechanical components. The workshop conducted a thorough AC diagnostic test and confirmed the control unit needed replacement. Total repair cost was 980€, including parts, labor, and system recharge. The repair took about 4 hours, and they tested the AC compressor thoroughly to ensure no additional issues. For proper diagnosis of your Lupo, it would help to know: Have you noticed any electrical issues before the AC failure? What specific error codes are you getting? Does the blower motor still work on any speed? When was the last time you had air conditioning repair or maintenance? This could narrow down if your issue is identical to what I experienced or if it might be something else in the system.

Following my last service at 114300km, I can confirm it turned out to be a refrigerant leak in the AC compressor seal, not the control unit. The auto AC repair specialist found the actual issue using a UV dye test, much more basic than initially feared. The automotive cooling system needed a new compressor seal kit (150€) plus labor (200€). They also performed a full cooling system pressure test and refrigerant recharge, which added another 100€. Total repair came to 450€, significantly less than replacing the entire compressor or control unit. Getting the specific error codes read first definitely helped avoid unnecessary parts replacement. The repair took about 3 hours, and the cooling system has worked flawlessly since. Would recommend having a proper diagnosis done before jumping to conclusions about the compressor being completely failed. A professional AC service might detect a simple refrigerant leak that could save you hundreds in repairs.

Thanks for sharing your repair experience. Your case shows exactly why proper diagnosis is crucial before replacing major components. While my Polo needed a control unit, your Lupo's auto refrigerant leak turned out to be much simpler to fix. Speaking from my repair experience, faulty control units often show similar symptoms to refrigerant leaks, which is why I initially misdiagnosed my own issue. My repair bill was over twice what you paid because of the electronic component replacement. After learning from both our cases, I would suggest anyone facing car air conditioning problems to: 1. Get error codes properly read 2. Have a UV dye test done to check for refrigerant leak points 3. Test electrical components if no leaks are found 4. Consider a full system pressure test The automotive cooling system in these VW models can be tricky to diagnose without proper testing equipment. Glad you got yours sorted for a reasonable cost and avoided unnecessary parts replacement. A full AC system inspection might cost more initially but saves money by identifying the exact issue, whether its a simple seal failure or a more complex electronic problem like in my case.

Appreciate the detailed follow-up about the control unit situation. After the repair was completed on my Lupo, the car air conditioning has maintained perfect performance for several months now. Interesting to learn that your Polo had electronic control issues, while my auto refrigerant leak ended up being much simpler to fix. The automotive cooling service cost breakdown shows how different our repairs were, your 980€ control unit replacement versus my 450€ seal and recharge job. Really highlights how similar AC unit issues can have completely different root causes. One update on my repair, the shop also found minor wear on the AC compressor belt during inspection, but it was still within specs so I saved money by not replacing it yet. They suggested monitoring it during future services. For anyone reading this thread with similar problems, getting proper diagnostic testing first definitely saved me from unnecessarily replacing expensive parts. The key was finding a shop with the right equipment to properly test both the mechanical and electronic AC components. Looking back, taking the time to get those error codes read and having the UV dye test done was absolutely worth it. Thanks everyone for the helpful input on troubleshooting these cooling system problems.