2006 GMC Sierra WT 5.3

royg · November 7, 2006

Once in a while my volt meter on my dash goes below 14 volts about 12 or 13. At night I notice that my head lights and dash lights give one flicker. I checked my battery and it has 100% charge and 100% state of health.

I went to an AC Delco charging system seminar last year and the instructor said that some new charging systems will decrease the charge when it's not needed, is this true and is this what's happening?

I called hte dealer here in Hawaii and they said that 12 to 14 volts is normal??? I thought that it was 13.8.

Help me plz, thank you

GM-Tech · November 7, 2006

You should have done a search. This has been discussed many times here. But, I'll be generous and post this once again. Read it carefully.

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Subject: Voltmeter Gage Fluctuation - keywords charge IPC generator engine electrical flicker intermittent light lamp low gage cluster voltage voltmeter wire volt #PIT3331C - (10/20/2006)

Models: 2005-2007 Cadillac Escalade, ESV, EXT

2005-2007 Chevrolet Avalanche, Silverado, Silverado Classic, Suburban, Tahoe

2005-2007 GMC Sierra, Sierra Classic, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL

with Regulated Voltage Control (RVC)

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This PI is being updated to add models and refer owners to the owners manual. Please discard PIT3331C.

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may comment that their volt gauge is fluctuating between 12 and 14 volts on their full size pickup / 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 turns off the alternator when it is not required in order to improve fuel economy. The alternator will turn back on when additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems which 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.

Recommendation/Instructions:

No repairs should be attempted and please reference the owners manual under Section 3 (Instrument Panel) "Voltmeter Gage" for more information.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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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