Infiniti Q's Battery Mysteries: Dim Lights & Hard Starts

Hey there! I had almost identical issues with my 2015 Infiniti QX70d (diesel) last summer. The symptoms you're describing match exactly what I experienced dimming lights and struggling starts. Initially thought it was just the battery, but my mechanic found it was indeed the battery temperature sensor that was acting up. Had it fixed at the local Infiniti dealership after my regular mechanic couldn't properly diagnose it. The sensor was sending wrong readings to the charging system, causing the alternator to either overcharge or undercharge the battery. They had to replace the sensor and recalibrate the charging system. Not a major repair in terms of complexity, but it's crucial to get it sorted soon as it can lead to battery damage if left unchecked. The whole thing took about 2 hours to fix. Been running perfectly since then, no electrical issues whatsoever. Hope this helps!

Hey, thanks so much for sharing your experience! It's really helpful to know I'm not alone with this issue. Sounds like we had the exact same problem and I'm glad you got it sorted. Do you mind me asking how much the repair set you back? Also, curious if you've had any other electrical problems since getting it fixed?

Hey again! Happy to help out! So yeah, after getting it fixed at the dealership, it cost me exactly 315€ honestly, it was worth every penny because the car's been running like a charm since then. The battery temperature sensor repair completely sorted out all those annoying electrical issues I mentioned before. Since you asked nope, haven't had a single electrical problem since the fix, which was a huge relief. My QX70d is working perfectly now no more dimming lights or dodgy starts in the morning! The dealership really knew what they were doing with this one. Quick heads up though might be worth getting it checked sooner rather than later. Like I said before, leaving it too long could mess up your battery, which would end up costing way more to replace. Honestly, sounds exactly like what I dealt with, so I'm pretty confident that's your issue too. Let me know how it goes if you get it fixed!

Thanks a lot for all the details! I actually went ahead and took your advice got it checked at the Infiniti dealership yesterday. Turns out you were spot on! It was the battery temperature sensor, just like in your case. The funny thing is, my repair cost was almost exactly the same, around 320 €. The mechanic was super professional and explained everything clearly. They fixed it in about 2 hours, just like you said. Took it for a drive this morning and what a difference! No more dimming lights, and it starts up perfectly now. Really appreciate you sharing your experience saved me from wasting time with my old mechanic who probably would've just replaced the battery unnecessarily. The dealership definitely knew their stuff. Thanks again for pointing me in the right direction! Catch you later!