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Low voltage issue

lance9386

By lance9386
in Troubleshooting & Recalls

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lance9386 Enthusiast

lance9386

Posted
Posted

Why is voltage dipping well below 14 when the truck is running?? It's intermittent, it will go back up to normal at times..

fondupot Senior Enthusiast

fondupot

Posted
Posted (edited)

RTFM. If the needle is within the hash marks to either side of 14 volts. Its fine.

 

Straight from my owners manual:

 

"When the engine is running, this gauge shows the condition of the charging system. The gauge can transition from a higher to lower or a lower to higher reading. This is normal. If the vehicle is operating outside the normal operating range, the charging system light comes on."

Edited by fondupot
  • Like 1
MNDaveC Enthusiast

MNDaveC

Posted
Posted

I'd certainly be keeping a close eye on things if it starts fluctuating if there were no obvious electrical drains. Belt slipping? Low RPM?

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

This is normal. Look through the forum or read the manual.

 

Someone posts this question like once a week. ;)

  • Like 1
lance9386 Enthusiast

lance9386

Posted
  • Author
Posted

Thanks guys. I did RTFM... but.. I have never seen a vehicle unable to maintain 14.4V while running unless there was a huge draw on the electrical system. I find that at idle is mostly when this happens. At night with the headlights on it stays right above 14, where it should be. I just think that is very strange, but apparently it is by design.

fondupot Senior Enthusiast

fondupot

Posted
Posted

Thanks guys. I did RTFM... but.. I have never seen a vehicle unable to maintain 14.4V while running unless there was a huge draw on the electrical system. I find that at idle is mostly when this happens. At night with the headlights on it stays right above 14, where it should be. I just think that is very strange, but apparently it is by design.

 

Its a design element that comes from the fuel efficient alternators on these trucks. When the battery is within an acceptable range, the alternator is not engaged, this is less draw on the motor which saves fuel.

  • Like 3
lance9386 Enthusiast

lance9386

Posted
  • Author
Posted

 

Its a design element that comes from the fuel efficient alternators on these trucks. When the battery is within an acceptable range, the alternator is not engaged, this is less draw on the motor which saves fuel.

Thanks for the explanation! That is good to know.

MMC Enthusiast

MMC

Posted
Posted

Saves fuel and extends battery life, GM's been doing this for years.

  • 10 months later...
Silver ice 6.2 Senior Enthusiast

Silver ice 6.2

Posted
Posted (edited)

I haven't seen a pic.. and thought I would post.. here you go when I first noticed i said oh wow that's nice..lmao bit looked online and seen that it's normal. And yes that was my reaction at first

post-145646-0-28256900-1436131420_thumb.jpg

post-145646-0-28256900-1436131420_thumb.jpg

post-145646-0-28256900-1436131420_thumb.jpg

post-145646-0-28256900-1436131420_thumb.jpg

Edited by Silver ice 6.2
  • Like 1
20L8TSierra24 Senior Enthusiast

20L8TSierra24

Posted
Posted

I was just thinking about this because my truck is barely starting at times. My needle looks like above and I load checked the battery and it came back good.

  • 9 months later...
thejimmian Enthusiast

thejimmian

Posted
Posted

does anyone with cooled seats notice a drop in seat fan speed when the voltage goes below 14v o nthe dash? I have recently noticed that when the truck turns the alternator off to save gas i basically loose the highest cooling level (fan speed is the same on level 2 and level 3). pretty annoying. i think it is the same story with the AC blower fan as well.

KLRV6 Enthusiast

KLRV6

Posted
Posted

 

Its a design element that comes from the fuel efficient alternators on these trucks. When the battery is within an acceptable range, the alternator is not engaged, this is less draw on the motor which saves fuel.

And the battery will last longer by not forcing higher voltage on it when not needed. I was worried when I noticed it the first time.

  • Like 1
  • 2 years later...
Kevin Gorczyca New Member

Kevin Gorczyca

Posted
Posted (edited)

Here is my 2017 Denali with the 6.2L and 35,000 miles. Notice my two pictures have different miles on the trip meter. I was driving around for 4 hours yesterday morning and it stayed this low the whole time. This line represents around 12 v. You mean to tell me that this thing was in fuel saver mode charging at 12v for half a day? I’m having tons of electric problems on my truck and the dealer is using this as an excuse to not find the real problem. I’m also having transmission shuddering and slipping trouble, severe detonating on 93 octane (only when it’s cold and dry out), and front parking sensors and crash avoidance sensors throwing codes. Had front power seat and rear wiper not work intermittently too. Dealer is just making excuses but I think in my case this is NOT operating as designed. Can anyone elaborate on this?

F433DB0B-83C9-4CE8-9457-A5D74A616943.jpeg

4793C5DA-EA7F-4EE6-85C5-1F29BA5E396D.jpeg

Edited by Kevin Gorczyca
Added engine size and mileage
  • 1 year later...
Nasir222 Enthusiast

Nasir222

Posted
Posted

I have 2017 Silverado LTZ Crew Cab and it stays low in the daytime and jumps to normal range at night and I have a decent audio system upgrade and never had problems before... or noticed it. I noticed that when I push the audio in the daytime I have a clipping monitor that shuts the amp down when it hits clipping that only has happened when it gets close to the left side mark of the 14v. Weird because I would have never known if I didn't have the clipping monitor on my amp 

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