Another Dead Battery

[Gangly]

2020 LT Z71 with the 5.3, ~3,900 miles purchased new approximately 2 months ago.

 

I washed the truck Saturday afternoon, let it sit over 24 hours, then went to start it Sunday night and got NOTHING.  That's when I noticed I had zero lights or sounds from the truck, and pressing the start/run button resulted in zero change.  No lights, sounds, door locks, or power anything.  I hooked up a fully charged battery and jumper cables to try and jump it, but the engine wouldn't even crank.  The lights and chimes worked, but nothing else.  I disconnected everything and now the truck is sitting in my driveway.  This is the second time this has happened to me with this truck and I'm not certain whats going on.  With a fresh battery connected via jumper cables, I checked to make sure I hadn't left any lights on or anything plugged in to the ports, but no lights were left on and no electronics were plugged in.  I have no clue what could cause the battery drain.

 

However I did notice one thing that might be of interest:  I usually press the door lock button twice on the FOB to make sure the truck is locked and the factory alarm is set,  but both mornings that I experienced a severe battery drain over night, I found my doors unlocked.  I am notorious for forgetting to lock my doors at least once or twice a month, so I wonder if by not locking my doors the PCM, Radio, or some other electronic is not shutting or cycling down?  Also, even with a fully charged battery, my doors will not automatically lock if I walk away from it so that again makes me wonder if the electronics are even shutting down when I forget to I lock the truck and set the factory alarm when walking away from it.

 

Irritating for sure, I'll be calling GM shortly.

[mafd2]

Why are you locking the doors with your fob when they auto lock? 

[Jav_eee]

Why are you locking the doors with your fob when they auto lock? 

He said they don’t automatically lock.


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[Thomcat]

Auto lock has to be applied in vehicle settings, the default is off.

 

Install some LEDs? Substitution of LEDs with improper resistance values for the stock halogens in the reverse lamps and directional/parking lamps can cause the perimeter lighting system controls and related systems to fail to sleep and even though lights are off the circuitry will continue to drain the battery.

[steve841]

1 hour ago, Jav_eee said:

He said they don’t automatically lock.


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They most certainly auto lock (cant speak for lower trims).  

 

Its in the menu of the infotainment.

[Jav_eee]

They most certainly auto lock (cant speak for lower trims).  
 
Its in the menu of the infotainment.

Well that’s all fine and dandy but he said HIS don’t. So that’s why he uses the button on the fob.


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[Gangly]

My door locks do not automatically lock though they are supposed to with my truck being an LT trim.  I have not checked the infotainment system options for auto locking doors so that might be something to check. 

 

The truck is at the dealership right now and I'll post any information I receive.

[Gangly]

1 hour ago, Thomcat said:

Auto lock has to be applied in vehicle settings, the default is off.

 

Install some LEDs? Substitution of LEDs with improper resistance values for the stock halogens in the reverse lamps and directional/parking lamps can cause the perimeter lighting system controls and related systems to fail to sleep and even though lights are off the circuitry will continue to drain the battery.

Nothing installed other than aftermarket GM floor mats and a Du-Ha under seat storage bin.

[TweetybyrdRT]

if it were and older truck id say have the shop check the voltage regulator,  if it's faulty it might be giving enough power to run but not run and charge.  I havn't even found my alternator yet on this truck

[TRKLGND]

On 4/20/2020 at 11:51 AM, Jav_eee said:

 

Well that’s all fine and dandy but he said HIS don’t. So that’s why he uses the button on the fob.


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They DO.  Just turn the feature on!

[Gangly]

  The technician requested to hold the vehicle at the dealership over night for testing and found a bad cell on the battery.  They replaced the battery and I asked that they hold the vehicle for another overnight test just to make sure and they called this morning to let me know everything passed.  I won't be able to pick the truck up for a few days but hopefully the problem is solved.

[Donnie Summers]

1 hour ago, Gangly said:

  The technician requested to hold the vehicle at the dealership over night for testing and found a bad cell on the battery.  They replaced the battery and I asked that they hold the vehicle for another overnight test just to make sure and they called this morning to let me know everything passed.  I won't be able to pick the truck up for a few days but hopefully the problem is solved.

Just dropped my 2020 GMC Sierra SLT off today at the dealer cuz my battery was dead the day after I took it home, 54 miles on truck... They too had me leave it over night for testing....

[Donnie Summers]

Must be somethun goin on they ain't tell'n me cuz they are keeping the truck all weekend, I'm hope it ain't serious.....

[steve841]

My brother had an F150 years ago that had perpetual battery drains.  Dealer couldn’t figure it out.  
 

eventually, he actually tracked it down to a dash setting that literally created an open circuit and killed the battery.....   Ahhhh the fancy high tech gadgets

[ILSilverado]

There is a TSB on this and it has to do with a short in a wire harness somewhere

Edited April 29, 2020 by ILSilverado