2016 Tahoe Z71 - Gauges turned off, kept driving OK. Shut off now won't start?

Will do my best to keep this concise and share pertinent info only:

I was driving my 2016 Tahoe Z71 with 111,000 miles home from 2 hours out and 100 miles. I stopped for gas about half way, filled up, no issues.

About 10 miles out, I noticed all the gauges were full lock left, reading 0. All of the sensors flagged alerts. Wipers, parking, ABS, airbags, etc. Center console had carplay on, and kept working. I thought that's weird, maybe I should stop and turn off the car, and when i turn it back on it will effectively "reboot".

I pulled off the freeway with 5 miles to home, pulled over to a safe spot with a shoulder and what not. Turned the vehicle off. When I went to turn the vehicle back on, nothing, some tapping (not clicking like a starter), and the dash did not light up.

AAA battery car came, checked battery, which was good. We both assumed it was a bad alternator.

Waited for the flatbed, with no juice, he couldn't even get it to move in to neutral. It was that dead/non operable.

Got a new alternator in preparation. Removed the old one, took it to O-Reilly to test it, they said it tested GOOD. Shit.

Pulled out the battery, tested it, 12.8v, a little low but also GOOD.

Checked the big fuses, GOOD (as far as I can tell).

Tried to connect a cheap OBDII reader I have, shows 0 codes. Great.. Also notice the climate info is in Celsius? Weird.

Open to any and all ideas!! Not good.

I had a Sierra do the same thing. Turned out to be an overcharging alternator that toasted the battery. When I stopped to get it check Auto Zone said both were good. When I got home to my own testers is when I found the issue.

ezmoney1981 said:

Will do my best to keep this concise and share pertinent info only:

I was driving my 2016 Tahoe Z71 with 111,000 miles home from 2 hours out and 100 miles. I stopped for gas about half way, filled up, no issues.

About 10 miles out, I noticed all the gauges were full lock left, reading 0. All of the sensors flagged alerts. Wipers, parking, ABS, airbags, etc. Center console had carplay on, and kept working. I thought that's weird, maybe I should stop and turn off the car, and when i turn it back on it will effectively "reboot".

I pulled off the freeway with 5 miles to home, pulled over to a safe spot with a shoulder and what not. Turned the vehicle off. When I went to turn the vehicle back on, nothing, some tapping (not clicking like a starter), and the dash did not light up.

AAA battery car came, checked battery, which was good. We both assumed it was a bad alternator.

Waited for the flatbed, with no juice, he couldn't even get it to move in to neutral. It was that dead/non operable.

Got a new alternator in preparation. Removed the old one, took it to O-Reilly to test it, they said it tested GOOD. Shit.

Pulled out the battery, tested it, 12.8v, a little low but also GOOD.

Checked the big fuses, GOOD (as far as I can tell).

Tried to connect a cheap OBDII reader I have, shows 0 codes. Great.. Also notice the climate info is in Celsius? Weird.

Open to any and all ideas!! Not good.

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your first clue if you haven't fixed this already is you have no voltage, so that means one of more of those battery top fuses may have a took a dump or one of the cables connected to it are bad. or you may have a really bad ground somewhere, you need to get a meter out and start checking starting at the battery.

Big Mama said:

I had a Sierra do the same thing. Turned out to be an overcharging alternator that toasted the battery. When I stopped to get it check Auto Zone said both were good. When I got home to my own testers is when I found the issue.

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Good to know, I will swap the alternator and see what happens. Nothing to lose.

Check what @Doubeleive mentioned before spending any more cash. He’s really good at helping figure this stuff out.

ezmoney1981 said:

Good to know, I will swap the alternator and see what happens. Nothing to lose.

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if you have key on, engine off and it shows 0 voltage then your issue is not the alternator, if you for some reason suspect it could even remotely be a bad alternator then simply unbolt the charge cable and try again. key-on, engine-off. you should see 12.xx on the gauge and thru the obd port with a scanner.
IF THIS IS THE CASE AS NOTED ABOVE (no voltage)
then go take your meter and check each of those fuse outlets on the battery top, each has a different rating i.e. 175a, 80a, etc, etc
if one of more of those are burnt (no continuity) then the vehicle may only get partial power, so you may have interior lighting but no power to the ecm, etc
those fuses are not serviceable you have to replace the whole unit and it runs about $120.
AND if one is burnt you need to figure out why, before you blow $120 by bolting up a new one and repeating the same end result.