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Re: battery light (6/16)
1/9/16 12:02pm

Sarge81

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WEST SENECA, NY - USA

Vette(s):
1981 Blue Ice Met. w/pearl ghost flames TKO500 5speed. LS1 Swap 3.45 Dana 44.

Joined: 12/3/2001
Posts: 2379

Voltage regulator is internal.

You should be getting around 13.75 volts (not Amps) at the battery. So you said the alternator was tested at Autozone and they were getting readings of 12-14 volts at the alternator. Something doesn't seem right. I don't trust those test machines at auto parts stores. I've taken alternators in and was told they were good when in fact they were not good. I would take the alternator down to a auto electric repair place that repairs starters and alternators, etc.

What does the voltage do when you turn on the headlights and heater fan?

How does the ground cable going from the battery to the crossmember under the car look?

And how does the ground cable from the engine to the frame on the underneath right side of the engine look?

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GEN III 5.7L "LS6" Engine swap
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Re: battery light (7/16)
1/12/16 4:24pm

kstyer

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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6424

The Autozone machine is okay for most checks, but not all.

You have the battery cable to the back of the alternator, then the smaller plug with two wires. The red one is ( or should be ) another battery source. You also have another small wire. This one starts at the ignition switch, and goes to the warning light, and then to the alternator regulator, which is inside the alternator. It feeds an ignition signal into the regulator to let it know it's time to turn on and go to work.

If the light comes on when the key is on engine off, it has a complete circuit, and grounds inside the regulator in the alternator. When the engine spins and the alternator starts to charge it puts power to this line. This creates a hot to both sides of the wire/bulb, and the light goes out due to equal voltage stopping current flow.

Unplug the small wire with the key off. Turn the key on, don't start the engine. If the alt light is on you have a wiring problem. If it is off, plug the connector back in. If the light comes on the circuit is fine. If it stays on when the car is started, you have an alternator/regulator problem.

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Re: battery light (8/16)
1/20/16 4:14pm

my80Vette
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Dacula, GA - USA

Vette(s):
1980 Corvette White and Black with Black interior. 350 V-8 Auto

Joined: 7/18/2015
Posts: 33

kstyer said:

The Autozone machine is okay for most checks, but not all.

You have the battery cable to the back of the alternator, then the smaller plug with two wires.� The red one is ( or should be ) another battery source.� You also have another small wire.� This one starts at the ignition switch, and goes to the warning light, and then to the alternator regulator, which is inside the alternator.� It feeds an ignition signal into the regulator to let it know it's time to turn on and go to work.

If the light comes on when the key is on engine off,�it has a complete circuit, and grounds inside the regulator in the alternator.�� When the engine spins and the alternator starts to charge it puts power to this line.� This creates a hot to both sides of the wire/bulb, and the light goes out�due to equal voltage stopping current flow.

Unplug the small wire with the key off.� Turn the key on, don't start the engine.� If the alt light is on you have a wiring problem.� If it is off, plug the connector back in.� If the light comes on the circuit is fine.� If it stays on when the car is started, you have an alternator/regulator problem.

P Ok I've unplugged the plug into the alt and turned the key and no light. When I plug it back in the light comes on. The alternator reads 14.5 volts and doesn't fluctuate when turning headlights on or turn signals. When driving the radio will shut off and the gauge lights will go out, I assume to conserve nessecary power but not sure. I finally was able to get under car and traced the positive and negative cables as best I could, at least until the Lh went into frame rail and from what I could see the cables looked ok. Not sure what to try next. Any ideas?

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Re: battery light (9/16)
1/21/16 4:11pm

cinor

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, - Canada

Vette(s):
1975 L48 Stingray 1992 LT1

Joined: 12/24/2013
Posts: 414

its possible one of your battery cables is not good as well, been there and took a long time to figure it out. They may look good but that doesn't mean anything. Things will still work maybe not as well or maybe not all the time, it can be very frustrating. took us 6 months to figure that one out.

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Re: battery light (10/16)
1/21/16 4:19pm

my80Vette
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Dacula, GA - USA

Vette(s):
1980 Corvette White and Black with Black interior. 350 V-8 Auto

Joined: 7/18/2015
Posts: 33

How did you figure out the battery cables were bad?

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Re: battery light (11/16)
1/22/16 8:24am

cinor

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, - Canada

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1975 L48 Stingray 1992 LT1

Joined: 12/24/2013
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well long story short We replaced two still problems. Then one day it stopped starting all together so just started fooling around banged on the one cable we didn't replace and the thing fired right up. You can not tell if they are bad by looking at them. It was crazy one day everything worked the next some worked and then the next nothing worked. It was one of those well we fixed everything else.

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Re: battery light (12/16)
1/22/16 8:30am

cinor

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, - Canada

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1975 L48 Stingray 1992 LT1

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I have to share another story. I belong to a classic car forum in Saskatchewan and there was a fellow on their who had the same problem and he had replaced many parts. I told him of my experience and told him to replace the cables, well the forum went on and on and guys were telling him to replace this check that and totally ignored me. Well guess what about a week later he came on and said he had a bad cable. Well I don't usually say much but this time I did and made a comment about me being female didn't mean I didn't know a few things... Lol could have went the other way too. This doesn't mean that is your problem but it just sounds sooooo familiar

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Re: battery light (13/16)
1/22/16 8:55am

Adams' Apple

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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
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my80Vette said: When driving the radio will shut off and the gauge lights will go out, I assume to conserve necessary power but not sure.

No systems will shut down to conserve electrical power. Is this issue(radio/lights) something NEW, or has this been happening all along? This particular issue is most likely related to your charge indicator light problem.
Cindy is right, too. A cable might show it is carrying voltage to/from the battery, but all that needs is ONE small strand of wire to work. However, that one strand of wire is not enough to carry the amperage the system needs to work.
It's kinda looking like you may have a problem under the dash...

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Joel Adams
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Re: battery light (14/16)
1/22/16 4:02pm

dskopp
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Oak Creek, WI - USA

Vette(s):
1981 Great White Shark. Red Interior, 350/190hp. PS, PB (SS), A/C CC, T-Tops, Going to remain as Stock as possible. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vetts Car Club. 175,000 Original miles!!

Joined: 5/21/2008
Posts: 1958

cinor said: I have to share another story. I belong to a classic car forum in Saskatchewan and there was a fellow on their who had the same problem and he had replaced many parts. I told him of my experience and told him to replace the cables, well the forum went on and on and guys were telling him to replace this check that and totally ignored me. Well guess what about a week later he came on and said he had a bad cable. Well I don't usually say much but this time I did and made a comment about me being female didn't mean I didn't know a few things... Lol could have went the other way too. This doesn't mean that is your problem but it just sounds sooooo familiar

Your a Female?????? What has that got to do with anything. Yup, your a female alright!! I have seen you and can confirm that as a fact!!!

All the comments that I see are all correct. There must be one of them therie "electrical gremlins" in his car. I also had that experience, turned out to be bad diaods!!

Dan da Man Handshake

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Re: battery light (15/16)
1/28/16 8:42pm

my80Vette
Former Member
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Dacula, GA - USA

Vette(s):
1980 Corvette White and Black with Black interior. 350 V-8 Auto

Joined: 7/18/2015
Posts: 33

Ok I found the "electrical gremlin"! After checking every cable and connection to the car I decided I would do something simple😳. I replaced "all" the fusses in the fuse panel. Even though none were blown, apparently one was still bad. As of now the light is off and the system is charging correctly😄. Thank you all for your help. I can't believe that it was a fuse. I guess they don't call it an idiot light for nothing!

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Re: battery light (16/16)
1/28/16 11:15pm

Adams' Apple

With glass fuses, it's hard to tell if they are good or not unless you use an ohm-meter. The fuse element may be good in the center, where you can see it, but, a lot of times, the element will break loose from the end caps. In that case, it may make contact at times, and not at other times.

It could also simply be a fuse is just not making contact with the fuse holder...a little corrosion can cause the same thing.
Glad you got it all handled, and thanks for letting us know what you found!! Thumbs Up

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