Problems with weak/flickering lights and battery start on 2009 Ford Flex - possibility of battery sensor fault

Hey, had the exact same problem with my 2007 Ford Mustang, so very similar to your Ford. I have a bit of experience with cars, so I'm not a professional, but I know my way around a bit. I then looked at the problem in my garage. As I understood it, the battery sensor microprocessor was defective. The repair cost me 315 euros. As the exact fault is quite specific, I would advise you to have it looked at in a workshop and confirm the specific fault. Can you explain in more detail what other symptoms you have? That might help me give you more details. Hope that helps you.

(Translated from German)

Hey, thanks for your quick reply and the helpful tips! All I can say about the other symptoms is that the engine sometimes jerks and the car doesn't warm up as quickly. I'll still follow your suggestion and take the car to the garage. The 315 euros mentioned are of course not a lot, but safety first, isn't it? With a mileage of 106071 km, there have hardly been any problems so far, so I guess it's still within reason. So thanks again, and I'll wait for opinions from others in the community.

(Translated from German)

Sure, no problem, that's what we're here for. Your additional symptoms could indicate a defective battery sensor. My Mustang had similar symptoms before the repair. And yes, the 315 euros were not easy to cope with. But in the end I was glad it was just that and I was able to solve it quickly. The engine ran much more smoothly in my car afterwards, so at least that should be better. Warming up a bit should also make it run faster. Regarding your mileage, in my case the problem occurred at around 115000 km, so you're still a bit early. It's best to discuss this with your garage and describe all the symptoms you've noticed. They will then be able to give you sound information. I'd be delighted if you could keep us up to date and let us know how it turns out. Good luck and hopefully everything will be resolved soon!

(Translated from German)

Hey, thanks so much for your quick reply and your detailed advice! Your experience really helps me. And you're right, I need to take the car to the garage and explain the symptoms in detail. A faulty battery sensor could really be the cause of everything. The repair costs are quite high, but I also see the value in getting my car sorted. I'll keep you posted when I know more. Your support means a lot to me. Thanks again and I hope I can give you some good news!

(Translated from German)