2015 Tahoe LTZ No start/NO crank/Random electrical issues

[Bulldog77]

2015 Tahoe LTZ
Lots of miles
The normal message doesn't come up on dash or audio screen when you enter the vehicle.
it will light up randomly after hitting the start/stop button a few times. Reference the attached picture.
It used to do something similar randomly over the years but normally a battery disconnect and it would go away.
The battery is brand new.
I cleaned the grounds below the inner fenders on both sides and ran a new one from the firewall.
Any ideas?
I have absolutely no clue where to start.

 

[the 18th letter]

2015 Tahoe LTZ
Lots of miles
The normal message doesn't come up on dash or audio screen when you enter the vehicle.
it will light up randomly after hitting the start/stop button a few times. Reference the attached picture.
It used to do something similar randomly over the years but normally a battery disconnect and it would go away.
The battery is brand new.
I cleaned the grounds below the inner fenders on both sides and ran a new one from the firewall.
Any ideas?
I have absolutely no clue where to start.

Check the battery cables, they can rot internally. May have to do advanced testing to detect it.

 

[Fless]

Start with a voltage drop test. It will tell if the main cables can handle a load or if they're compromised, or if the body ground is bad, etc.

A good code reader that can read body codes (whether they're active or history) might give some clues as to what's going on. Maybe a loss of communication between modules.