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Alternator / Gauge: Voltage

Blue2500CC

By Blue2500CC
in Ask A GM Technician

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Blue2500CC Enthusiast

Blue2500CC

Posted
Posted

My '10 1500 5.3 is doing something weird IMO. When you first start the truck, and for a short time, the needle indicating the voltage, according to the dash gauge, is actually almost completely past the 4 of the 14. After a short while, the voltage output according to the dash gauge actually drops below the 1 of the 14. It is almost like after the alternator "warms up" the output is dropping.

 

I haven't called the dealer YET, figured that will be later this week when I have a little time.

 

Any thoughts??? Or am I just crazy and this is "normal" for the newer trucks???? My 2k never had a drop like this, and alwasy stayed above 14 volts according to the gauge.

 

RPM's do not seem to matter either.

 

Thank you!

Chris

LeoS41280 Enthusiast

LeoS41280

Posted
Posted

Some customers may comment that the volt gauge fluctuates between 12 and 14 volts on their 2005-08 full size pickup or utility vehicle. Starting with the 2005 model year, these vehicles are equipped with a Regulated Voltage Control (RVC) system. RVC reduces the targeted output voltage 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 causes the voltmeter to fluctuate between 12 and 14 volts (fig. 16), as opposed to non-regulated systems which usually maintain a more consistent reading of 14 volts.

 

 

 

fig16.jpg

 

This fluctuation with the RVC system is normal system operation. No repairs should be attempted. Refer to the owner manual Section 3 (Instrument Panel) Voltmeter Gage for more information.

 

TIP: Refer to PIT4426 for concerns with keeping a camper or trailer battery properly charged.

Zembonez Senior Enthusiast

Zembonez

Posted
Posted

13.8 Volts is "normal". Keep in mind that the gauges only "approximate" the actual output of the alternator. Most are somewhat accurate but not right on the money.

Z'06 Enthusiast

Z'06

Posted
Posted
Starting with the 2005 model year, these vehicles are equipped with a Regulated Voltage Control (RVC) system.

 

Good to know. Can this be tuned out of the PCM?

Blue2500CC Enthusiast

Blue2500CC

Posted
  • Author
Posted

Leonard,

 

Thank you! As just asked, is this something than can/should be reprogrammed?????? Or only if there is an issue maintaining a charge? I wondered if this was something that was designed.

 

Jim,

 

I realized there are tolerances, but thought this had to be the alternator due to the amount of change. But you never know till asking or "digging in" and checking.

 

TY!

Chris

LeoS41280 Enthusiast

LeoS41280

Posted
Posted

If your not having any trouble, leave it alone. It also is suppose to help increace the life of the battery when it goes into fuel saving mode.

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