My 2001 F350 7.3L diesel will intermitantly become a no start or slow crank, normally on cooler days, even though the truck has been plugged in for hours.
The key point that I have noticed is that the radio cuts out during the glow plug cycle, and will sometimes get a clicking noise from behind the dash. Also when I am snow plowing with this truck the radio will cut in and out when operating the plow, Seems like a low battery voltage, but it checks out ok,

I have tested the batteries(both good), checked resistance of the positive cable right to the starter(.3ohms), Tested resistance of negative cables to engine and body ground(.3ohms),

Any help and suggestions would be appreciated.