the red and white wire are seperate and not connected to the battery on mine .dont have a photo yet but gm had a plug that connected the white and red together .just those 2 .ive used that same system on my mud trucks .and some old military trucks not sure what will happen if you hook all 3 together .disconnect the red wire from the alternator first .if that doesnt work my geuss is the alternator was bad 'my memory isnt as good but i believe and 80s camaro and several other gm vehicles had the 1 wire alternator last one my kid bought was 35.00 bucks at napa good luck on your project
Alternator ground question (1 Viewer)
- Thread starter jvincig01
- Start date
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- Thread starter
- #22
OK so an interesting thing happened. I have an Odyssey battery with an Odyssey charger/tender. I usually hook it up if I am not going to drive it for a few days... longer times in the winter.
Anyhow, I charged it up and was around 13v when I took it off. After about 10 minutes off the tender it dropped to 12.5v... no big deal right? I decided to run it and test the alternator and it started charging the battery at 14.4v. So the alternator works!
However, it looks like the battery loses a ton of juice in a short amount of time. I checked for a parasitic draw and found nothing. Could I just have a bad battery? It's only 1.5 years old. Would the alternator not try to charge if its at 11v?
Anyhow, I charged it up and was around 13v when I took it off. After about 10 minutes off the tender it dropped to 12.5v... no big deal right? I decided to run it and test the alternator and it started charging the battery at 14.4v. So the alternator works!
However, it looks like the battery loses a ton of juice in a short amount of time. I checked for a parasitic draw and found nothing. Could I just have a bad battery? It's only 1.5 years old. Would the alternator not try to charge if its at 11v?
After charging the battery will settle down to 12.5
12.5 is pretty close to float. Memory says 2.09 per cell x 6 = 12.54 on a new battery.
You could take the battery to an auto parts store and have them put a load test on it to make sure.
My thought is if the battery was bad enough not to charge on the alternator then it shouldn't have worked on the one-ten battery charger.
Try to remember what you did just before the alternator kicked in.
If the battery has enough poop to crank the engine and is good enough to take charge from the wall unit then it should work with the alternator.
It is probably going to turn out to be something simple.
One night long long ago I was coming home and the alternator stopped charging while driving.
I was pulling my trailer so had those pre-led running lights plus the lights on the Toy.
I could tell the lights were getting dim but didn't realize just how much until I down shifted for a steep grade and the alt. kicked in and everything got bright outside.
Next day pulled the alternator apart to find a lose wire inside.
- Thread starter
- #25
Thanks for all the advice guys. I went out this morning after leaving it off the tender and checked the volts. It was at 11.5. My battery is only 2 years old so I have a warranty on it. I pulled it and will have the place where I bought it test it out for me. Although not my best skill, I actually enjoy tracking down these sorts of electrical issues.
Sounds like your battery is bad.
Let me apologize for jumping in here but it is apparent each of you knows more about alternators and the electrical system then I do. If you have time would you mind jumping over to the following post and render an opinion: Need Help with the Last Wire
I have looked at the wiring diagram for my 79 FJ40 as well as other models and can't find this wire. I failed to note in my original post that there appears to be the remnant of a ring terminal under one of the bolt heads securing the front engine lift fitting. The wire in question is fairly thin probably 16 ga.
Again my apologize for jumping in here.
If you do reply please do so under my original post.
I have looked at the wiring diagram for my 79 FJ40 as well as other models and can't find this wire. I failed to note in my original post that there appears to be the remnant of a ring terminal under one of the bolt heads securing the front engine lift fitting. The wire in question is fairly thin probably 16 ga.
Again my apologize for jumping in here.
If you do reply please do so under my original post.
