83 K10 that i'm doing a ground up on. Truck functioned fine when taken apart. I labeled all connections and where they went. Months ago when i started reassembly i had the cab on 2x4's not bolted down. I have been successfully starting/idling the motor with the braided strap on the little firewall stud, starter hot all normal but the ground cable from the battery would only crank the truck if i put the end on the alternator bracket/other engine component. It would power up but not crank if i put the end of the cable on the PS frame rail like it was originally located.
I now have the cab bolted to the frame correctly which i thought would complete any grounds needed from cab to chassis.Today i got curious and cleaned up the frame and bolted the negative cable there. Truck powered up and barely cranked.. braided firewall ground started smoking. The only other wire that isnt connected is the rad support ground wire. I figured i didnt need that except for headlights etc. I am horrible at wiring so i tried to label everything very clearly and take pictures of exactly where it came from. This has me a bit stumped.