Loss of electrical power

[Matthew Deuster]

Bout two year ago my 16 Denali w/ 5.3L would lose all power, brakes, steering, dash, radio intermittently for about 2 seconds. Finally got the service tech to replica the problem and they swapped out the batter fuse box. Now it’s doin the same thing but the the whole truck shuts off and won’t start for a few minutes. I cleaned a bunch of grime out of the key hoping maybe the ignition switch was failing to read the key was in the ignition. Couple days ago my collision alert system started chiming for no reason either. When the truck did start back up it had me roll the windows down and up and the dash reset to factory settings. When I turn the key off and cycle the drivers door open and close the radio and some lights stay on. 
 

At first it seemed to only happen during maxed out left or right hand turns but now it does it while driving down straight. 

[Rysn James]

Where you able to figure out the problem, mine is doing the same thing

[Locking Lug Nut]

I had these same issues.  Ended up being numerous broken grounds, corroded negative battery cable wire in the middle of the cable and corroded and broken ecm cable $2000 later, it runs great again.