Well I've had my 2010 Silverado 4x4 5.3L for about 4 months now. Here recently I've noticed that the volt gauge will spike up to 15v and drop down to 12v. I went to a dealer and they said that the truck has a command charge function and that it's normal?? Never heard of this and being a tech for a semi trucking fleet for years I've always seen lose connections or altenator failure. But hearing from a friend that these trucks do have a computer that regulate items and operate differently than what I'm used to, I'm open to suggestions. I've checked all connections and all are tight. Symptoms: Headlights flicker when turning on turn signals or operating the windows, and while operating or sitting the volt gauge erratically jumps. To me this would be a sincere alternator issue. But again I'm used to all the non computerized equipment. So any thoughts on this or am I right in my process and came to the right conclusion???

 

Is this helpful?

 

Like you, I'm old school. I'd get a voltmeter to start, and check the alternator output at the battery terminals. As you probably know, the output should be around 14 volts, depending on engine speed and battery condition. If the readings are consistent, perhaps the problem is the gauge in the cluster.

And cleaning and tightening connections at the alternator and battery is never a bad idea.

Can't help when it comes to the computer end of the truck.

 

test your battery and voltage at the battery but yes the charge rate is regulated by the ecm