Shut down troubles

You've got an intermittent short in the accessery wiring.Probly only does it when it vibrates and rubs just right.I would pull the dash apart and follow all the harnesses to see if you can spot sonething.same goes for the harnesses around the engine and under dash area,fuse block,and fire wall also you might try the wiggle test.while its running shack harneses and wires see if you can get it to shut down to try and pin point it. Check behind ignition switch. I once had a cummins doing the same thing turned out to be a white for a add on near the altanator rubbed through and would POP the breaker intermittently.