Alternator not Charging Battery
02-16-2008, 08:52 PM
#21
Instructor
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Well thank you all for your advice, Im going to leave this one the pro's i guess. I think this thread has run its course, you were all a great help. You all have given great input, thank you so much.
I would like however to respond to D.T. If I knew i was going to be graded, I would have studied real hard before asking for advice from you. Even though you still refer to the battery light on the dash that I dont have, and to check the alternator again although i already did twice, must have missed that one too earlier on in the post. Ill in return give him the same grade he gave me, a C- in front of everyone for his review of the thread. I personally would have sent a PM.
I like THAT smiley 
I would like however to respond to D.T. If I knew i was going to be graded, I would have studied real hard before asking for advice from you. Even though you still refer to the battery light on the dash that I dont have, and to check the alternator again although i already did twice, must have missed that one too earlier on in the post. Ill in return give him the same grade he gave me, a C- in front of everyone for his review of the thread. I personally would have sent a PM.
I like THAT smiley
02-17-2008, 10:10 AM
#22
Heel & Toe
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Location: St. Boni MN
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I'm assuming you got a CS-130 or CS-144
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
...the above text is from:
http://www.idavette.net/hib/reman.html
that's the guidelines I used to wire mine in and it worked from the get-go.
"If you are unsure which adapter to use, measure the resistance of the exciter line. Disconnect the positive battery cable and the alternator plug. Connect an ohm meter between the #1 terminal on the plug end of the alternator harness and the end of the positive battery cable. Turn the ignition key to the "on" position and read the ohmmeter. If resistance is less than 35 ohms, use adapter #8078. If it’s between 35-350 ohms, use #8077. If it’s more than 350 ohms, you have excessive resistance somewhere in that circuit which needs to be repaired, first."
...the above text is from:
http://www.idavette.net/hib/reman.html
that's the guidelines I used to wire mine in and it worked from the get-go.
Who are the "pros" you mention that you are going to bring it to? I wouldn't give up and keep trying to fix it yourself. The costs of the specialized tools you buy and the experience are better spent on yourself rather than the "pros" in my opinion.
Last edited by D.T.; 02-17-2008 at 10:12 AM.
02-17-2008, 10:46 AM
#23
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No LIGHT in the 71 dash, just ammeter.
Regards,
Alan
Regards,
Alan
02-17-2008, 11:27 AM
#24
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You said your battery goes dead..... have you ever cut open a battery cable that runs under a car for years and years? Even if it looks fine i have seen them so corroded and white filled, i have know idea how they even worked.....
02-17-2008, 11:42 AM
#25
Heel & Toe
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Could be the OE ground (neg) cable also. Since the vette uses a non metallic body, old rusty ground connections to the FRAME go bad as well. Since the car is 37 years old.
02-17-2008, 11:42 AM
#26
No dice yet?? Geez! 
I like that first smiley.
Anyway, your battery light should work on the dash. Unequal voltages to and from the battery/alternator mean the light comes on. I would work on getting the dash battery idiot light fixed first. If you don't have one, well you better know 4 sure. Looks like you need to study a little harder. So far you are getting a C- grade on your troubleshooting skills...
Info on the CS...
http://www.alternatorparts.com/cs130_sbpage3.htm
I like that first smiley.
Anyway, your battery light should work on the dash. Unequal voltages to and from the battery/alternator mean the light comes on. I would work on getting the dash battery idiot light fixed first. If you don't have one, well you better know 4 sure. Looks like you need to study a little harder. So far you are getting a C- grade on your troubleshooting skills...
Info on the CS...
http://www.alternatorparts.com/cs130_sbpage3.htm
02-17-2008, 12:25 PM
#27
Heel & Toe
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OK, I get a C- also. I just want the guy to fix it himself. I hate bringing my vehicles to the "pros". I think we are all pros here at this site. I'll keep trying if Bnine will...I have received MUCH GREAT information on these internet forums over the years about how to fix it yourself and repair problems. The "real" problems and solutions seem to come up. Face to face sometimes people won't tell you the real story related to their own personal agenda. Hopefully I can help others as some have helped me.
Last edited by D.T.; 02-17-2008 at 12:32 PM.
02-17-2008, 01:26 PM
#28
Melting Slicks
Your missing the L connection. It is the Field Exciter circuit and comes from the ground side of the GEN light. The other side of the GEN light has battery voltage on it.
To test it, find the white wire in the harness, check it for voltage and it should read slightly under the battery voltage. Ground it and the GEN light should come on bright. If not your missing something. If it does light, connect it to the L terminal and you should be good to go
To test it, find the white wire in the harness, check it for voltage and it should read slightly under the battery voltage. Ground it and the GEN light should come on bright. If not your missing something. If it does light, connect it to the L terminal and you should be good to go
I made a test stand for alternators and without the Field Exciter- small light and until I added the small light all the alternators I checked were bad until I added the small bulb.
02-17-2008, 04:23 PM
#29
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The old corvettes used an ammeter instead of a voltmeter. Usually when I see a voltmeter going below 12VDC, something is wrong with the alternator or the battery. I haven't seen an ammeter in modern use at all lately.
Now with the ammeter, how do you know something is wrong? It measures the current difference between the alternator output and battery positive terminal. It should go down when you turn on the key and spin the starter, then come back up just past "0" when running?
Seems just like the same operating deal as a battery light in modern vehicles. When you turn the ign on, the battery light comes on, and goes out when you start the vehicle (if current is equal in both directions).
Bnine said in his first post that the ammeter was at "0" or no current difference in either direction, to and from the battery/alternator. Like mentioned earlier, your battery should be charging. It should stay below 0 if the alternator was bad.
Ever thought of testing the battery? If it never gets charged, how can you use it Bnine? Do you put it on an external power supply for a recharge every time you drive it?
Now with the ammeter, how do you know something is wrong? It measures the current difference between the alternator output and battery positive terminal. It should go down when you turn on the key and spin the starter, then come back up just past "0" when running?
Seems just like the same operating deal as a battery light in modern vehicles. When you turn the ign on, the battery light comes on, and goes out when you start the vehicle (if current is equal in both directions).
Bnine said in his first post that the ammeter was at "0" or no current difference in either direction, to and from the battery/alternator. Like mentioned earlier, your battery should be charging. It should stay below 0 if the alternator was bad.
Ever thought of testing the battery? If it never gets charged, how can you use it Bnine? Do you put it on an external power supply for a recharge every time you drive it?
Last edited by D.T.; 02-17-2008 at 04:38 PM. Reason: nothing better to do...
02-17-2008, 06:05 PM
#30
Le Mans Master
Here is something to try, since your car does not have an alt or gen light, start it up and make sure there is power to the batt wire which you have said it does. Make sure there is power to the s wire and then momentarily apply power to the L terminal, it should then charge until you turn the engine off. That will tell you if you alternator and internal regulator are good. Once the alternator begins to charge there will be power at the L terminal even with that wire disconnected. I believe it will read about half of the battery voltage. I am not sure if you can leave full ign switched voltage to the L terminal, perhaps someone will chime in.
02-18-2008, 10:47 PM
#33
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I had the same problem I also have what you added and changed out my gauges had to add a bulb to the excite wire and all is good you can mount it where ever you like.The bulb excites the alternator at start up and idle if you rev it up fairly high it usually will start charging with out the bulb the bulb wakes it up at start up while it idles.
