Truck Repair: KW w/N-14 cummings wont start, sec delay, wire harness

Question
After taking care of that, it did crank properly. Now it's been a couple of hours and I went back out to crank the truck and it won't crank. The c/e light won't go off which leads me to believe that the codes are gone. What now?
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-----Question-----
I just had a new clutch put in my 96 KW (n-14 cummings). After installation, it will not crank. It turns over but won't crank. All fuses have been checked. All wiring has been checked. Normally when starting the truck the check engine light comes on then goes off. Now that C/E light doesn't even come on while trying to crank it. What can be checked? HELP HELP
-----Answer-----
There is a 3 wire harness coming from the batteries to the ECM wiring for unswitched battery power.They are hooked up wrong or came unplugged.The 2 wires together are for POS & the single wire is NEG.

Answer
To check codes,trun key on & let the key on cycle finish.Then turn cruise to ON & bump SET switch.It should flash the yellow light for the 3 digit codes with a 1 1/2 sec delay & RED stop eng light between faults.Let me know what the codes are.Will be a 434 for low battery voltage.