Alternator/Battery issue with Silverado?????

I have a 2000 silverado ext 4x4 5.3l that I have been having a little problem with.

A few days ago I was driving and noticed the battery light come on and the volts gauge was reading around 10 -11volts. I turned off all accessories and headed her for home.

Once home I took the battery (delco factory) to Canadian tire for them to test it. It tested ""replace". So I did with a new 875cca terminator battery. When I installed the new battery the truck started fine but I noticed the battery warning light was still on. I let it run for 20min or so to see if it would charge. (or what ever was wrong might magically fix itself) The light didnt go out so I tried some of the accessories to put a load on it. The wipers and blower motor ran but noticeably slowly.

I just decided to let the truck run with all accessories off. The battery light didn't go out so after running for 1/2 hour or so I shut off the truck and the the battery now shows 11.7V across the terminals.

I charged the battery back up to show 12.6V across the terminals.

Then I started the truck and checked the voltage across the terminals with the truck running (no access on at all)......11.3V....What the.....and the bleeping battery warning light is still on.

I tried revving the truck to 2000-2200 rpm (no access on at all) and the voltage across the battery went up to 11.49 at one point but it also fluctuated down to 11.27 also....

Does this sound like a new alternater to go along with my new battery???? What are the odd that both the battery and alternator would crap on the same day???

PS. I have never had another issue with this truck until this.

Reply to
g.holden
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Hello, we just purchased a 1999 Silverado 1500 and love it except the battery kept going dead (We don't use it everyday). we replaced the battery and the same thing happened with a brand new battery. The guys who replaced the battery did a diagnostic and nothing else showed up except "replace battery". We are taking it back there for another look at the diagnostic.

I called the local Chevy guys and they said nothing common was happening to the 99 truck, but on the internet there are plenty of old posts about this very thing happening. i can't get in touch with any of the old poster because the reply option has expired.

Your problem is not identical, but related. So if you get any info on this, it may help us with our problem and vice versa.

good luck, elaine and don

snipped-for-privacy@msn.com

snipped-for-privacy@sympatico.ca wrote:

Reply to
egagne2

"Odds" has nothing to do with it. Your charging system developed a problem and your battery ran down because of it. Proper diagnostics would have identified this.

Reply to
aarcuda69062

Sounds like a alternator has failed to me. It happens. Pete

Reply to
Pete

I have posted this over at gm-trucks.com also and had a pretty good reply. The guy said that it is quite common for a bad battery to kill an alternator or a bad alternator to kill a battery.

Looks like its quite common too........ I'm gonna buy an alternator and put it on. Hopefully I will have some luck with this.

Reply to
g.holden

Generally a bad battery will put such a load on an alternator over a period of time that it will eventually kill it. The alt has been working overtime to keep the bad battery charged. Finally when the alt gave up, you will notice the bad battery.

James

Reply to
James1549

Might also be noted seven year old truck with original battery if I read the post correctly.

Whitelightning

Reply to
Whitelightning

Greetings,

First, consider yourself lucky that you got 6 years out of an original equipment battery. I seldom get more than three.

To answer your question, if you are not getting 13.8 volts or more when your truck is running then your alternator is dead - and Yes, yours is dead.

It is not unusual for a bad battery to kill an alternator, and/or a bad alternator to kill a battery. Either way, you've replaced your battery so now go replace your alternator (before your bad alternator kills your new battery as well).

Cheers - Jonathan

Reply to
Jonathan

That's the way I read it too. And, that's about when the alternator went on my '96 Silverado. The battery store should have found this before they put in the new batt.

Reply to
Mike Copeland

Hi!

Of course it did...I can't imagine any way a depleted battery would test good. It needed to be charged up before you had it tested. Your old battery sounds like it would have taken a charge and might have been fine after it did.

You should look into the possibility of bad connections or alternator failure.

William

Reply to
William R. Walsh

your alt is bad. With the engine running you should have

having a little

come on and

off all

tire for them

875cca terminator

started fine but I

run for 20min

might

some of the

motor ran but

off. The

or so I shut

the terminals.

terminals.

the terminals

all)......11.3V....What

on.

at all) and

point but it

new

alternator would

"Odds" has nothing to do with it. Your charging system developed a problem and your battery ran down because of it. Proper diagnostics would have identified this.

this.

Reply to
Boots Crofoot

That statement is not entirely true. It is not uncommon to have an internal shorted battery that draws so much current, that a known good alternator can not keep up the amperage to keep it charged, causing the lower voltage output. Running an alternator at full-field will eventually cause it to overheat, fail, etc...

James

Reply to
James1549

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