Intermittent starting issues

[NewbWrench]

2015 Yukon XL Denali
I am currently chasing an electrical issue that is fairly new. I have three key fobs, two I programmed myself (Amazon fobs) and one OEM that came with the vehicle. I haven't had an issue with any of the key fobs at all.

Recently I started having issues trying to start the vehicle. I'll get in, drive, no issues but then I park and come back to the vehicle and it's completely dead. Not even the accessories will turn on. Jump starting will sometimes work. I put a new battery in, checekd all the fueses that I could associate with any issues and couldn't find anything.

Sometimes when I push the start button the vehicle won't turn on but the anti-theft will come on. I have to get turn off the car, get out, lock it, and re open the door to start the car without the anti-theft enabled.

I dropped the car off at a mechanic last week and they said the following today:
Day 1 - No issues, started up with every key fob
Day 2 - Wouldn't start with any key fob - acted like the battery was completely drained
Day 3 - Would only start with one key fob

I am at a bit of a loss trying to figure this out.

 

[Big Mama]

Welcome to the forum from Virginia. Did the mechanic say the battery was dead on day 2? Did he have to jump start it on day 3? Did he check your battery cables, especially the grounds?

 

[Doubeleive]

2015 Yukon XL Denali
I am currently chasing an electrical issue that is fairly new. I have three key fobs, two I programmed myself (Amazon fobs) and one OEM that came with the vehicle. I haven't had an issue with any of the key fobs at all.

Recently I started having issues trying to start the vehicle. I'll get in, drive, no issues but then I park and come back to the vehicle and it's completely dead. Not even the accessories will turn on. Jump starting will sometimes work. I put a new battery in, checekd all the fueses that I could associate with any issues and couldn't find anything.

Sometimes when I push the start button the vehicle won't turn on but the anti-theft will come on. I have to get turn off the car, get out, lock it, and re open the door to start the car without the anti-theft enabled.

I dropped the car off at a mechanic last week and they said the following today:
Day 1 - No issues, started up with every key fob
Day 2 - Wouldn't start with any key fob - acted like the battery was completely drained
Day 3 - Would only start with one key fob

I am at a bit of a loss trying to figure this out.

the top of the battery panel is basically (a fusible link) one big fuse with different legs and different amperages on each leg
each connection goes to a seperate system on the vehicle
I would disconnect all of them wire brush all of it and reconnect, for beginers.
there are several grounds that should be checked also, 2 are right behind each front wheel on the body which get covered in all kinds of road gunk.