Never really dabbled in Reddit but let's see what happens ok on to the story.

Bought a 2020 Sierra w 107k on the dash. Drive it home and it sits for about a week until I drive it again.

We go for ice cream and one of the kids leaves the interior light on (I think) I go to drive it again in another week and it won't start.

Try jumping it but it's dead dead. I wait awhile with the cables on and the truck finally turns over. I pick up some wood at depot 10 months up the road and it sits again for a few days or so.

I go to cvs ( not important) and the truck seems to start slow. I don't drive it enough so maybe that's how it starts ( I'm thinking ). Bring it back homes it sits for a few days. Go to start it and boom dead again.....

Jump it, bring it to autozone. Autozone says the battery is fine " prob the alternator"

I bring it home I'm beyond annoyed, I do some things around the house, look up how to change the alternator, go back outside start the truck, dead again.

I call the small dealership (60 miles away) explain everything and he says that I have a 30 day warranty and it is now 34 days but he will work with me,mind you a drive maybe 40 miles with it since I picked it up, he will provide labor and I buy the parts the alt will be about 300.00

He tells me to start the truck and pull the battery cables. If it dies s then it's the alternator. I do that and the truck stays running.

Now I start it daily and let it run for 30 min. it is sluggish to turn over. Like it's weak, Something seems to be draining the battery. I am bringing it to an actual gmc dealer since I have more faith in them but my wife notices the ESC service light is on when she turned it on. I also know I'm prob looking at a 200.00 bill just to diagnose it thru gmc

That was a mouth full, anyone have any useful thought or experience like mine? Thanks in advance everyone