N14 wont crank over

That is your starter solenoid. You don't need it with modern starters with a magnetic switch. The amperage draw is the same.

Grab your 12v DMM and test in this order:

voltage at battery
voltage at battery key to start
voltage across the two SMALL wires at the solenoid in the picture while key is on start, it should be the same as the voltage across your battery no less .1v
if there is a difference test each small wire individually directly to ground on the battery with key to start. This will help isolate if it's a positive or ground issue.
That solenoid should make a nice clean "click" sound while key is on start
One large wire at the solenoid should be 12v constant, and the other is switched on by the solenoid, check both

If you still don't find a problem, check the switch wire to the starter(this one is switched on by the solenoid above) right at the starter. If there's still no issue it's your starter.

 

That is the mag switch coming off the key it energizes the starter solinoid, You need to test the voltage at that switch to it and thru it then at the starter check the ground and power wire to the switch also. I once drove a hundred miles to tighten the ground wire /mounting screw.
Just a thought!

 

Hit the starter with a hammer and try to crank it.

 

If you hit a starter with a hammer you loose the core.
Just a thought!

 

Don't hit it that hard lol! Just a few taps.

 

If it was ok when you parked it, I would say maybe batteries are dead, just a thought

 

I have n14 fld120 haul a short load 60 miles truck ran good started missing cut truck off changed filter now turns over like batteries dead changed batteries new starter cables the road service says engine stuck 3 ft bar can turn motor any ideas

 

Did you try starting it with ether and see if it would run?

Check the ECM fuse at the battery.