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Old 09-15-2010, 01:16 PM
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Electrical Alternator light on and gage showing discharging

I am working on a 1980 L-82 Corvette. I recently had the Choke heater light and Alternator light go on. I replaced the Choke Relay and the choke light went out. Alternator light still remains on and the gage shows discharging. I since replaced both the alternator and battery. Took both to Auto Zone and check out bad ( wondering if all do the same, because I am having same problem). I have checked the gage fuse and Choke heater fuse and both are good.

Appreciate any help on what to do next.

L-82

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Old 09-15-2010, 03:42 PM
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Welcome to the site. If you post this in the electrical section someone will try to help you.


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Old 09-15-2010, 07:04 PM
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Electical Problem

Sorry new at this don't know how to get in the Electrical problem catagory?
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Old 09-15-2010, 07:31 PM
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Quote:
Originally Posted by L-82
Sorry new at this don't know how to get in the Electrical problem catagory?
Go to the top of the page and click on bulletin board, And then click on the section that says electrical. Then look at top of that page to the left and click new thread and title your thread and type your question and then submit..Hope this helps.


Cole
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Old 09-16-2010, 06:50 AM
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Old 09-16-2010, 07:04 AM
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Thank you, I will check later for any responses
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Old 09-16-2010, 03:18 PM
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I am confused. Did you replace the battery and alternator and the problem persists or are you just wondering why they all failed at the same time.

It is not uncommon for a bad battery to eventually cook the alternator. I dont think the choke relay would be related
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Old 09-16-2010, 06:29 PM
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Once the problem started with the electric choke light on and the Battery Gage and Light on. I did replace the Electric choke relay and the choke light did go out. The Electric choke Fuse was OK. I replaced the Alternator first I took it to two Auto Zones for testing and it tested bad, but passed at two NAPPA stores. I went ahead and replaced the alternator because I was not charging the battery. Tested it with volt meter and was same as not running. I then took the battery to Auto Zone and it failed. I replaced the Battery and the volt meter still shows discharge and the Alternator light is still on. Still not charging the battery. I plan tomorrow is getting under the car and make sure all the wires to the Starter are OK and not grounding.
I am working on a 1980 Corvette.

Appreciate any advise.

Thanks,
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Old 09-16-2010, 11:33 PM
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According to the wiring diagram there is a fusible link in the red wire going from the alternator to the starter selenoid. Maybe that's blown.
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Old 09-17-2010, 06:12 AM
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Check the 2 small terminals on the alternator with the key on. They both should have voltage. The #1 may not have full battery voltage as it goes through the idiot light or on cars with a gause there sometimes is a resistor in the line.
If you have voltage at both terminals then the alternator should charge. If the voltage is missing, you need to trace it back to see why. Could be a broken wire, blown fuse or fuse link etc.

To test temporarily you could feed the #1 and #2 terminals on the alternator with battery voltage and see if it charges. THIS IS NOT A PERMANENT SOLUTON.

If there is voltage at both check to be sure the alternator has a good ground, Corvettes are notorious for grounding issues.

If all of this checks ok, you have a bad alternator.

You need to keep in mind, Autozone is in the business of selling parts, it is in their best interest to tell you the alternator is bad.
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Old 09-17-2010, 08:18 AM
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Chet, thanks for the feed back. I check with the ignition switch on and got voltage at terminal 2 of 12.16Volts and 1.5 volts on terminal 1. started the car and terminal 2 still was at 12.16 volts and terminal on was went up to 13+ volts, but instantly went to 0. Actually may tester went to 1 but it was not a correct reading.

My plans this morning is to crawl under the car and check all connections at the Starter. I replaced the starter back in March. I might as well pull it and have it checked to make sure it still is good. Don't seem to have any problems starting it when the battery is charged. When it becomes weaker the Bendex drive does make some noise sounds like arcing.

Again thanks for your feedback. If I cannot get it working today, I have made reservations with a Corvette mechanic on Tuesday to bring it to him and hope he can fix it.

Ed
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Old 09-17-2010, 08:51 AM
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I should have told you to pull the connector off to test the voltages as the alternator could supply feedback voltage.
Make sure you a re pulling the connector off and testing for voltage at the connector.
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Old 09-17-2010, 08:53 AM
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Quote:
Originally Posted by L-82
Chet, thanks for the feed back. I check with the ignition switch on and got voltage at terminal 2 of 12.16Volts and 1.5 volts on terminal 1. started the car and terminal 2 still was at 12.16 volts and terminal on was went up to 13+ volts, but instantly went to 0. Actually may tester went to 1 but it was not a correct reading.

My plans this morning is to crawl under the car and check all connections at the Starter. I replaced the starter back in March. I might as well pull it and have it checked to make sure it still is good. Don't seem to have any problems starting it when the battery is charged. When it becomes weaker the Bendex drive does make some noise sounds like arcing.

Again thanks for your feedback. If I cannot get it working today, I have made reservations with a Corvette mechanic on Tuesday to bring it to him and hope he can fix it.



Ed
The 1.5 volts is most likely you issue. That is the exciter wire for the alternator. Look at a diagram and see what feeds it.
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Old 09-17-2010, 03:52 PM
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Chet,

Pulled the two wire connector from the alternator and checked the voltage with the ignition on (Engine not Running). Terminal 1 showed 11.98 volts. Terminal 2 showed 12.49 volts.

Any ideas?

Thanks
Ed
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Old 09-17-2010, 08:43 PM
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Quote:
Originally Posted by L-82
Chet,

Pulled the two wire connector from the alternator and checked the voltage with the ignition on (Engine not Running). Terminal 1 showed 11.98 volts. Terminal 2 showed 12.49 volts.

Any ideas?

Thanks
Ed
Bad alternator, bad ground? Try running a jumper wire to terminal 1 and 2from the battery positive terminal. If it the alternator doesnt put out, and you are sure it is gounded then it is bad, if it does put out there is something wrong in the wiring. A bad connection will sometimes be able to pass voltage with no load but will fail when a load is put on it
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