VW Caddy AC Failure Points to Compressor Malfunction

I faced almost the exact same auto AC repair issue with my 2014 VW Golf last summer, and I have some experience working on basic vehicle HVAC systems. The symptoms you describe match what happened with my car, but it turned out the AC unit issues stemmed from a faulty control unit rather than the compressor. When the control unit fails, it can mimic compressor failure symptoms since the system wont engage properly. The repair involved: Complete diagnostic scan, Testing the control unit signals, Replacing the car air conditioning control module, System pressure testing, Recharge of refrigerant Total cost was 980€ including parts and labor. Much better than replacing the whole compressor which would have been considerably more expensive. To help diagnose your specific case, could you share: Does the fan still blow air (just not cold)? Are you getting any specific error codes? When exactly did the automotive cooling system stop working, suddenly or gradual failure? Have you noticed any unusual noises when trying to engage the AC? This information would help determine if your issue matches what I experienced or if its truly a compressor problem.

Thanks for sharing your experience. My car has been running fine until this point at 127891km with regular maintenance, last service was just 2 months ago. Some additional info that may help diagnose the cooling system issue: The fan blows but no cold air at all, Error code P0645 shows on scanner, Car air conditioning stopped working suddenly during highway driving, No strange sounds, system just wont engage, No signs of auto refrigerant leaks visible underneath I appreciate the detailed breakdown of your repair process. The control unit diagnosis makes sense given the complete system shutdown. Will have the shop check that before proceeding with more extensive repairs.

Good to hear back about your Caddy AC situation. After reading your additional details, Im even more convinced your issue mirrors what I experienced with my Golf. The error code P0645 specifically relates to the AC clutch relay circuit, which aligns perfectly with a control module failure rather than a compressor issue. The sudden failure during highway driving without any warning signs or refrigerant leaks matches my experience exactly. My system also showed similar symptoms, fan working but no engagement of the cooling components. Since your car just had service and shows no visible leaks, this strengthens the case for an electrical rather than mechanical failure. My vehicle HVAC system returned to perfect operation after the control module replacement, and the repair cost significantly less than a full compressor replacement. A few suggestions based on my repair experience: Request testing of the clutch relay circuit, Have them check the control module voltage outputs, Verify the AC compressor clutch is receiving proper signals, Get the AC unit pressure tested to rule out any hidden issues If these checks confirm a control module issue like mine, you should be looking at a repair cost around 900-1100€ rather than 2000€+ for a compressor replacement.

Thanks for all the detailed suggestions. I went ahead and showed the shop your responses, and they agreed to start with testing the control module and relay circuit before jumping straight to the compressor replacement. Just had the diagnostic tests done today: Relay circuit test confirmed intermittent voltage issues, AC compressor clutch not receiving proper signals, No mechanical problems found with the compressor itself, System pressure tests showed normal levels Turns out the control module was indeed the culprit. The repair cost came to 890€ including parts, labor and a system recharge. Much better than the 2200€ estimate for a new compressor installation. The vehicle HVAC system is now working perfectly again. No error codes and the cooling performance is back to normal. Really glad I got this second opinion before authorizing more extensive repairs.