Truck would not start

[dguptill]

I started my truck and drove around some, stopped and started a couple times, then stopped at fuel pump and shut the truck off. Filled the tank with diesel and tried to start the engine. All I got was a loud click. Engine wouldn't turn over. Did this a couple times. A friend noticed that the fan made a part turn each time I tried to start. He checked the battery connections and found the positive on the drivers side battery loose. He twisted the battery connection and the engine started on my next try.
My question, why couldn't the passenger side battery spin a hot engine? Does the system detect a poor battery connection and prevent an engine start? Or does the Cummins just require both batteries to start a hot engine? The batteries are 5 years old and I am planning to replace them now, just wondering.

 

[jhenderson]

The passenger battery is wired to the drivers side battery. The drivers side then feeds the starter and fuses. If the connection was loose on the passenger side your truck would have started with a good connection on the drivers side.

 

[Ozymandias]

Crossover wire is bad. Otherwise it would have started.

 

[TRAMPLINEMAN]

Just because the batteries are five years old doesn’t mean they’re bad. Do what you want, but just because you had a loose connection and/or bad crossover cable doesn’t justify new batteries.

 

[jhenderson]

Crossover wire is bad. Otherwise it would have started.

Not necessarily.not that it can’t happen, but I’ve never heard of a 4th gen crossover cable going bad. They bolt together at the drivers battery, along with a 250 amp fuse. If the drivers clamp was loose who’s to say what the crossover cable connection or the fuse looks like?
Ps. I’d do a voltage drop test on the disconnected cable before replacing it.

 

[dguptill]

Not necessarily.not that it can’t happen, but I’ve never heard of a 4th gen crossover cable going bad. They bolt together at the drivers battery, along with a 250 amp fuse. If the drivers clamp was loose who’s to say what the crossover cable connection or the fuse looks like?
Ps. I’d do a voltage drop test on the disconnected cable before replacing it.

I looked up the parts that are part of the battery cable wiring. The diagram shows on the drivers side battery, on the negative post, there is a "Battery Sensor, Mopar (4692269AI) .
Does anybody know if the sensor will stop the the starting cycle if there is a loose battery connection?
The truck is starting fine now so I guess I'll hold off on new batteries.

Thanks for the comments.

 

[AH64ID]

These trucks are very picky with voltage, so it's possible the ECM was aborting the start on you.

I'd run what you have and see what happens.

 

[SnoKing]

I see your truck is a 2015. Time for new batteries! My 2015 got new batteries last Sept. Very common life of OEM batteries being low. These trucks do not slow crank, the start process is aborted instead.

 

[Cummins12V98]

Dumped mine before mine dumped me last September at 4 yrs 6 mo.