voltage gauge

[fun in dirt]

Just noticed the other day that my voltage gauge was reading below 14 (like at about 12), then looked at it again & it was reading above 14 (where I thought it normally did). Is this normal?
I would think it should run about 14 all the time. It's not having any problems starting or anything else wierd.
Oh yeah it's a '07 1500 with 5.3

[jgreene0717]

I have had a 07 and now have a 09. They both did it and it states something in the owners manual about it. If I recall it is for fuel savings. Do not no if that is true but I believe that is what it states in the manual.

[CRUBCHECKER]

Normal operation read below


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#07-06-03-009B: Information on Voltmeter Gauge Fluctuation Due to Regulated Voltage Control System and Concerns About Camper/Trailer Battery Charging - (Feb 5, 2010)


Subject: Information on Voltmeter Gauge Fluctuation Due to Regulated Voltage Control System and Concerns About Camper/Trailer Battery Charging


Models: 2005-2010 Cadillac Escalade Models

2005-2010 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe

2005-2010 GMC Sierra, Sierra Classic, Yukon Models




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This bulletin is being revised to add the 2010 model year. Please discard Corporate Bulletin Number 07-06-03-009A (Section 06 - Engine/Propulsion System).


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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 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.

Camper/Trailer Battery Charging Concerns
Some customers may comment that when towing or hauling a camper/trailer, the auxiliary battery for the camper/trailer will not stay charged. In most cases, this concern is blamed on the new RVC system. While the RVC system does reduce the generator's targeted output voltage to 12.6-13.1 volts when in "Fuel Economy Mode", this feature is bypassed if the tow/haul feature is enabled. With the tow/haul feature enabled, the RVC system will stay in "Charge Mode" and the targeted generator output voltage will be 13.9-15.5 volts, depending on the battery state of charge and the estimated battery temperature. To keep the generator in the "Charge Mode", use either of the following two methods.

• The first method is to use the tow/haul mode when towing or hauling a camper or trailer.

• The second method is to turn on the headlights, which will increase the generator's targeted output voltage to 13.9-14.5 volts.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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