BMW M3 A/C Dead: Help Needed for Compressor Issue

Had the same issue on my 2016 BMW M4 last summer. The A/C compressor shutdown was triggered by an undervoltage condition in the electrical system. Turned out my voltage regulator was failing, which caused inconsistent power supply to the A/C system. Initially thought it was just the compressor, but my mechanic ran a proper diagnostic. They had to replace the voltage regulator and recalibrate the electrical system. The A/C compressor itself was actually fine, it was just going into protection mode due to the unstable power supply. It was a serious issue that needed immediate attention because it could have affected other electrical components in the car. The repair wasn't just about getting the A/C working again, but preventing potential damage to other systems. After the fix, everything's been running perfectly, including the A/C. Don't just look at the symptom, make sure they check the entire electrical system. It's worth finding a mechanic who knows BMW electronics well.

Thanks for sharing your experience, that's really helpful info. My M3's symptoms sound exactly like what you described. I'm actually relieved to hear it might just be the voltage regulator rather than the whole compressor system. Would you mind telling me roughly what you paid for the repair? Also, has everything stayed working properly since the fix, or have you noticed any other electrical quirks?

Hey there! Following up on your questions about the repair costs, I actually ended up paying 240 € for the voltage regulator fix, which honestly wasn't as bad as I initially feared. It was definitely worth every penny because the A/C has been working flawlessly since then. I'm really glad I shared my experience because you're right, the symptoms do sound identical. And to answer your other question: nope, haven't had a single electrical issue since getting it sorted. The A/C kicks in perfectly every time, and all other electrical systems are running smooth as butter. My mechanic really knew their stuff with BMWs, and diagnosing it as an undervoltage problem rather than jumping straight to replacing the whole compressor saved me a bunch of money. Just make sure whoever looks at yours checks the electrical system thoroughly, that's the key here. Trust me, once they fix that voltage regulator, you'll be back to enjoying your perfectly cooled M3 in no time.

Just got back from the mechanic, and wow, am I glad I asked here first! Turns out my issue was indeed electrical, but slightly different from yours. The main relay for the A/C system had failed, and there was a loose connection in the wiring harness. The mechanic showed me the corroded relay, it was completely shot. The repair came in at 180 € total, including parts and labor. Much cheaper than I expected, especially after my last mechanic quoted me for a full compressor replacement! The best part? The A/C is now blasting cold air like it's brand new. The mechanic also did a quick check of the entire electrical system just to be safe, and everything else looked good. Thanks again for steering me in the right direction. Really helped me avoid getting ripped off for an unnecessary compressor replacement. Also found a honest mechanic in the process, think I'll stick with them for future repairs. It's such a relief having this sorted without breaking the bank. Time to enjoy some properly cooled drives in my M3!