6.0 No Start???
Live in middle Tennessee and woke up two mornings ago and it was 28 degrees, 05 6.0 cranked right up fine (was not plugged in, no block heater). Drove 50 miles shut truck off for about 30 min started again fine. Drove 5 miles to local hardees for breakfast, get to the drive thru and turn truck off to order and it wont start back acting as if batteries/alternator was problem. Pushed truck out of drive thru and pulled batteries and took to advance auto and charged all night and tested good. Took batteries back and put in truck still very slow cranking. Hooked up a set of jumper cables to each battery and hooked to 06 cummins. Let set for 10 min tried to start still nothing acting as if batteries are just weak, then hooked 2 large fully charged Snap On jump boxes to each battery on top of the cables. Nothing. Not exactly sure what the problem might be, the obvious would be bad batteries but i feel that it could have something to do with my ficm but not sure. PLEASE HELP ASAP! Need truck back quick as possible. Any help would be greatly appreciated.