I have had a strange thing happen twice now. I drive my truck daily, at least a couple hours a day. Recently, I would get into my truck in the morning, and it acted like the batteries were dead. Turn the key, and the truck would "attempt" to turn over, but wouldn't do it. The first time, I figured well the batteries are bad. Had a buddy of mine give me a jump. When the cables were connected, I didn't even give it 30 seconds before I tried to start it. It started like there was no issue. Had the batteries tested ( still connected to the truck) and they tested good. Drove the truck for a couple of weeks with zero issues. This morning, the same scenario. As soon as the cables were connected, truck started right up. This time, I noticed that the fuel gauge read empty for a few minutes, then gradually caught up.
The second issue, could be completely unrelated. Over the past month or so, I have noticed that occasionally the steering wheel controls would not operate correctly. Example, menu up button operated as the OK button, volume up button would change the mode of the radio. This is also intermittent.
Does anyone have experience with these issues? I also posted this question in the Super Duty Forum
BTW, my truck is 2017 F350 diesel, 4x4, CCLB

 

I believe there is a low voltage safety in these trucks, ie. below X volts it won't let the truck start. put a start pack or jump it and the computer sees over X volts and lets it start.
I may be totally wrong about that though, either way I don't own a diesel truck with batteries that are over 3 years old, at 3 years they get replaced regardless of condition. cheap insurance in my opinion.

 

Each battery needs to be tested independently as they are connected in parallel. If either battery is low and needs to be replaced, it's recommended to replace them in pairs.

 

Thanks for the replies. I’ll stop on my way home from work tomorrow and get the batteries load tested. Then go from there.

 

load test them disconnected so there is no draw from the other battery.

I would also be inclined to crawl under the truck and check the wiring harness that runs under the cross member. Check it for chafing.