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Voltage gauge on the high side???

gone_fishing
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gone_fishing Enthusiast

gone_fishing

Posted
Posted

I've only had my new Sierra a couple weeks now but have noticed that the voltage gauge usually seems high (to me at least). When first started up in the morning the needle is far enough to the right of center that I can see the entire number 14 on the gauge. I have a Scan Gauge so I pluged that in too see what it says. I was seeing readings as high as 15.2 volts when driving this afternoon. It was about 34F today so is their a relationship between higher voltage and cold weather?

 

Thanks

DaveH71 Enthusiast

DaveH71

Posted
Posted

Its supposed to do that. GM has been using variable charging alternators for awhile now. The needle will dip as low as 13.5 and as high as 15 or so. The gauge isn't very precise. The PCM will dial back the alternator when full amp production is not needed to save fuel such as a deceleration event or when not many accessories are on. It will increase amperage output when a high draw is seen such as when a lot of accessories are on etc.

 

Your truck is A-ok and is working exactly how it is supposed to.

newdude Senior Enthusiast

newdude

Posted
Posted

The charging system is basically computer controlled. It can boost or drop charge based on current system voltage, temperature, etc. The system voltage varies with duty cycle. The more % duty cycle, the higher the voltage output.

mcnwil Enthusiast

mcnwil

Posted
Posted

I have been watching my volt gauge and wondering why the swings from 13-15 with no apparent reason. This makes sense now, thanks for the information. These gauges seem pretty accurate to me. They are certainly better than the Ford dummy gauges!

DanielAcosta Enthusiast

DanielAcosta

Posted
Posted

What I have noticed is the voltage is higher after the truck has sat for a few days. Once the battery is fully charged, the voltage drops down. Makes sense and I like it.

 

One of the reasons I decided to trade my 07 Tundra is the voltmeter started fluctuating for no apparent reason. When it sits at one spot for years and then starts to change, something is amiss. The dealer checked it, found no problems and said don't worry about it. I was still concerned, though, because alternator replacements on Tundras are pricey.

  • 6 years later...
Kenk New Member

Kenk

Posted
Posted

I have a 2016 Silverado and my voltage gauge won’t go back down to 0 when the truck is off. It will go down to 15 and the stay way above 19 when I’m driving it  

JimCost2014 Senior Enthusiast

JimCost2014

Posted
Posted
1 hour ago, Kenk said:

I have a 2016 Silverado and my voltage gauge won’t go back down to 0 when the truck is off. It will go down to 15 and the stay way above 19 when I’m driving it  

Welcome to the site.

 

Sounds like your needle is "off", there was just a post from another member where his temp gauge is off in the same manner.

JimCost2014 Senior Enthusiast

JimCost2014

Posted
Posted
1 hour ago, Kenk said:

Do you know how to fix it 

This is what I found:

 

On 7/4/2020 at 2:19 PM, MartyMinogue said:

Hi,

I just noticed something strange happening with my temperature gauge. It seems like the needle is not pointing in the correct direction. I’m attaching a video to show what it looks like. Any help would be greatly appreciated!

 

 

Yes, the needle has moved for some reason. I have seen this multiple times. The good thing about this is it is an easy fix. Remove the cluster and take the outter glass off. reinstall the cluster and turn the igntion on when the engine is completely cold. Remove the needle by GENTLY prying up on it and put it back at 0. Test it to make sure its working correctly and then reinstall the glass.

Very easy repair.

  • 1 year later...
mikeyk101 Senior Enthusiast

mikeyk101

Posted
Posted
On 2/24/2022 at 10:52 AM, Henry Krencis said:

Good luck fishing

Amazing and extremely insightful first post. Did you join just to post this??? 

pokismoki Senior Enthusiast

pokismoki

Posted
Posted

the truck alternator has a special charging algorithm,  by charging at 15.4 volts this blows off sulfides and balances each cell in the battery. it shouldnt charge this high for more than 45 minutes

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