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Username Post: alt/voltmeter ?        (Topic#348491)
Senior Member
Posts: 1667

Loc: kingman,az
Reg: 04-29-00
11-30-17 01:42 PM - Post#2716431    

my 82 year old friend has an 2016 chevy truck [like a C-1500 or whatever they # them as now] anyway, after driving about 30 miles the volt meter goes way down after while it goes back to 14 V. he is worried.
I wonder if the computer is shutting the alt. off to save gas, and then turning it back on when the bat. requires a boost. old time generators worked like this. whereas most alts. charge all the time, and use HP.
am I right or wrong? is the truck OK or not?
Thanks Rod in AZ

Posts: 1172

Loc: Mission,BC
Reg: 02-03-05
11-30-17 03:24 PM - Post#2716442    
    In response to rod

GM started doing this ~10 years ago

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factory L48 350 Chev,TH350,PW,PT
99 Silverado RCLB 4.8 NV4500 14BSF 4.10's locker 6" Procomp 35 bfg m/t's 9k winch cutout flares
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Dedicated Member
Posts: 5373
Loc: Lake Superior-Michigan US...
Reg: 03-30-00
12-03-17 01:32 PM - Post#2716757    
    In response to rod

Read the owner's manual page 138.

  • Quote:
Subject: Information On Voltmeter Gauge Fluctuation Due To Regulated Voltage Control System And Concerns About Camper/Trailer Battery Charging

Models: Cadillac Escalade Models
Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe
GMC Sierra, Sierra Classic, Yukon Models

Voltmeter Fluctuation Condition:
Some customers may comment that the voltmeter is fluctuating between 12 and 14 volts on their full size pickup or utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities are equipped with a new Regulated Voltage Control (RVC) system. This system reduces the targeted output of the generator to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The generator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted.

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2018 Polaris RZR S 900 EPS

Posts: 153

Age: 51
Loc: Limerick, PA
Reg: 09-16-08
11-12-18 12:03 PM - Post#2751165    
    In response to elcamino

I have a 2012 Silverado 1500. The voltmeter often goes above 14 volts. Usually around 16. Anyone else have this problem? I don't get any indication that anything else is wrong.

Honored Member
Posts: 27510
Loc: Katy, Tx, USA
Reg: 07-06-00
11-12-18 06:09 PM - Post#2751201    
    In response to GMDave

14 to 14.5 = good.

I would suspect the voltage regulator if consistently above that.

Yours is kind of a middle ground. I've had a regulator go to near 18V, that's cause for repairing it right now, as if nothing else you'll blow every light bulb on the truck if you let it run more than a few minutes.

Honored Member
Posts: 27969
Loc: San Francisco, CA
Reg: 11-26-02
11-19-18 08:47 AM - Post#2751769    
    In response to Rick_L

  • Rick_L Said:
.....I've had a regulator go to near 18V, that's cause for repairing it right now, as if nothing else you'll blow every light bulb on the truck if you let it run more than a few minutes.

It won't do the battery any good either.


Those who choose an automatic transmission want transportation. Those who choose a manual transmission want to drive.

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