Mechanics

CHEVY CHARGING SYSTEM

2007 Chevrolet Silverado

Electrical problem
2007 Chevy Silverado V8 Four Wheel Drive Automatic 88000 miles

My 2007 Chevy P/U seems to have an alternator problem. When hot, the voltage will drop to 12.5 sometimes and stay there, then for no reason, jump back to 13.7-14. Engine revs or electral load don't seem to matter. It has every electrical accessory available with a 160 amp alternator. The battery is relatively new also. The voltage drop is slow, not sudden, as is the rise. I've checked every connection I can find, to the point of checking terminal grip. I was an ASE Master tech before closing my shop a few years ago, and would've sold a customer an alternator already. I'm on disabilty now, and $275 is a big chunk of money. Do you have any ideas of something I might've missed?
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Jim Shirron
June 15, 2010.




I have sen alot of GM gauges be off and read different than what is actually happening at the alt. Did you take readings at the alt to see if they coincide with the gauge?

Tiny
Jack42
Jun 15, 2010.
Yes, I've made a thing that will allow me to plug my Fluke into a cigarette lighter outlet, plus checking at the alt. And the battery also.

Tiny
Jim Shirron
Jun 15, 2010.
Sure sounds like a regulator that is having troubles. You have already checked all of the usual suspects with something like this (connection quality).I probably would go after the alt as well, since actual load doesnt make any difference and it seems to be pretty random.
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Tiny
Jack42
Jun 15, 2010.
BTW I dont mean to solicit so blatantly, but we are always looking for good techs to help out on the site, you can contact Mike@2carpros. Com for the info if you are interested. Once you gain Moderator status you will be paid per question answered, alot of our Mods are guys on disability who cant actually turn the wrench anymore but have a wealth of knowledge to share

Tiny
Jack42
Jun 15, 2010.
Thanks for your info. I was afraid I needed an alternator, but wanted someone to agree with me. I wish they sold parts for alternators like they used to, but such is life. I would like to help out if I could. Getting paid is not really necessary, but a littie extra cash would be nice. It gets old sitting here with nothing to do but mow the yard with the rest of my family gone all day to school etc. Let me know if I can, and if so, how and what to do. Thanks again.

Tiny
Jim Shirron
Jun 15, 2010.
Email Mike@2carpros. Com he will fill you in on what you need to do to become a moderator. Would be great to have more help

Tiny
Jack42
Jun 15, 2010.
Jim, my name is Louie, and I am extremely well known on the IATN as an expert on alternator/charging problems. The probability is there is absolutely nothing wrong with your vehicle because it is a computer controlled version of the GM RVC (regulated voltage control) or SARVC (stand alone regulated voltage control) system. http://www.motor.com/article.asp?article_ID=1606 If there are not any PCM alternator codes then there are not any charging problems, or a bad alternator. Louie

Tiny
Louieservice
Nov 14, 2014.

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