VW Beetle AC Dead: Compressor vs Relay Investigation

Recently dealt with similar symptoms on my 2011 VW Golf TDI. The A/C system complete shutdown pointed to an electrical protection mechanism, which is actually a good thing as it prevents serious compressor damage. In my case, the A/C compressor was shutting off due to low voltage protection. The root cause was a deteriorating battery causing voltage fluctuations, triggering the safety cutoff. The HVAC system has specific voltage requirements to operate safely. A proper diagnosis revealed: Battery voltage dropping under load, Corroded battery terminals, Worn alternator bearings affecting charging While the refrigerant leak check came back negative, the A/C compressor itself was fine. The fix required replacing the battery and alternator to restore proper voltage to the electrical system. This was a significant repair but far less costly than replacing the entire A/C system. Suggesting a full electrical system diagnosis before assuming A/C component failure. Low voltage issues often masquerade as A/C problems, especially in VAG diesel vehicles of this generation.

Thanks for sharing that detailed solution. My issue turned out similar but with a pressure sensor fault and damaged belt tensioner that was causing erratic A/C compressor operation. Im curious, do you remember the total repair cost in your case? Also wondering if youve had any other A/C system issues since getting it fixed? My VW has been running great after the repair but always good to know what to watch out for.

Following up on my earlier VW Golf TDI issue, I got everything sorted with a 240€ repair to fix the undervoltage problem affecting the A/C system. The mechanic found and corrected the electrical issues that were causing the A/C compressor to shut off. The A/C has been working flawlessly for over 8 months now. No pressure sensor problems or refrigerant leaks to report. The key was getting a proper diagnosis of the electrical system rather than just assuming A/C component failure. Regular maintenance has kept everything running smoothly. Worth checking the pressure switch and belt condition during annual service to catch any potential issues early. Good practice to run the A/C for a few minutes weekly, even in cooler weather, to keep the system properly lubricated. Your pressure sensor fault repair was a smart fix. Those sensors are critical for protecting the A/C compressor from damage. Glad to hear your VW is also running well after addressing the root cause.

Thanks everyone for the insights. Wanted to share how my repair experience turned out. After getting a second opinion, took it to a certified VW shop who properly diagnosed the issue. The AC relay had failed, and there was a faulty pressure switch causing the system to shut down. Also discovered the previous shop had damaged the belt tensioner during unrelated work, which was affecting the A/C compressor operation. Total repair came to 380€ including parts and labor. They replaced the pressure switch, AC relay, and belt tensioner assembly. The HVAC system is now working perfectly again. Much better experience with this shop, they took time to explain the diagnosis and showed me the worn parts. Been about 2 months since the repair and no issues so far. Running the A/C regularly as suggested to keep everything lubricated. Lesson learned about getting proper diagnosis from qualified techs instead of quick fixes that might cause more problems later.