BMW 3 Series: Multiple Climate System Failures & Error Code

Hi there! I've got some experience with cars, and this sounds very similar to what I faced with my 2015 BMW 5 Series Hybrid (had the 7 Series too). The symptoms you're describing are exactly what I dealt with. After struggling with it for a few days, I took it to my regular workshop. Turned out it was just a faulty connection in the temperature control wiring harness. The mechanic found some corroded cables and plug connections affecting the whole climate control system. They replaced the connections, and everything went back to normal. Cost me around 95 Euro, pretty reasonable considering I was worried it might be something major! But before jumping to conclusions, could you share: Have you noticed any other electrical issues? Does this happen all the time or intermittently? Are there any other warning lights on your dash? This would help determine if you're facing the same issue I had. These BMWs can be tricky with their electronics, but usually, it's something fixable.

Thanks for sharing your experience! Had similar symptoms with mine too. Just got it serviced at 101668 KM and still dealing with this. What's interesting is that my issue is pretty consistent, happens every time I start the car. No other electrical problems though, just the climate control system acting up. The workshop initially thought it might be the control module, but after reading your post about the wiring harness, I'll definitely have them check the connections first. These hybrids can be quite sensitive with their electrical systems. Really appreciate the tip about the corroded cables, could save me from unnecessarily replacing the whole unit. Did your BMW throw any specific error codes when this happened? Mine's showing one, but it's not very descriptive.

Hey again! Thanks for the follow-up about your BMW. Yeah, mine was showing an error code too, one of those vague ones that could mean anything. When my issue happened, I was getting code P0073, which basically just points to the circuit for the ambient temperature sensor. The consistent nature of your problem sounds exactly like what I experienced. Every single start-up, same issues. What really tipped off my mechanic was when he noticed some green residue around one of the connector pins, classic sign of corrosion in these BMWs. Speaking of the hybrid system, these cars are super sensitive to electrical gremlins. After they fixed mine, the mechanic showed me the old wiring harness, and you could clearly see where moisture had gotten in and started causing problems. It's apparently pretty common in these models. One thing I forgot to mention earlier, before getting it fixed, I noticed the temperature readings would sometimes flash briefly before going dead. Did you notice anything like that? Also, my repair has held up perfectly for about 18 months now, so once you get those connections sorted, you should be good to go. Let me know what your mechanic finds. I'm curious if it's the same issue I had. These BMWs may be fancy, but they sure can be finicky with their electronics!

Thanks so much for all those details! You've really helped me understand what might be going on with my BMW. Actually, yes, I've noticed that same flashing temperature reading you mentioned! It flickers for a second or two before going completely dark. That's a huge relief knowing yours was fixed with just a wiring harness repair and has stayed good for 18 months. I've scheduled an appointment with my mechanic for next week. I showed him your messages about the corroded connections and the P0073 code. He says it sounds spot-on and wants to check the wiring harness first thing. Mentioned he's seen similar issues with other BMWs too. You're absolutely right about these hybrids being finicky with electronics! But honestly, when everything's working properly, they're amazing cars. I'll definitely update you once it's fixed. Really appreciate you taking the time to share your experience, saved me a lot of worry about potentially needing to replace the entire control module! Take care and thanks again for all the help!