Alt issue ... Oops ....
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Alt issue ... Oops ....
Short of it is when working on car ( 1980 vette ) I shorted the main lug on the back of the alt . When I started her up I had 12v on volt gauge and a battery light on.
I assumed I blew the alt voltage regulator , replaced alt with new . Have same issue . I put v meter on battery and sure enough with car off or started I have basically the same voltage reading ( a tad lower with car running)
So I am not charging , I went to alt and tested that main power wire on rear of alt , with car off I have zero voltage , with it running I have tons of voltage . So apparently alt works but that wire is dead
I tried to follow that main wire and it runs from alt down by itself into the frame and I am guessing back behind driver seat to battery ?
Anyway anyone have any ideas or advice for me .
I assumed I blew the alt voltage regulator , replaced alt with new . Have same issue . I put v meter on battery and sure enough with car off or started I have basically the same voltage reading ( a tad lower with car running)
So I am not charging , I went to alt and tested that main power wire on rear of alt , with car off I have zero voltage , with it running I have tons of voltage . So apparently alt works but that wire is dead
I tried to follow that main wire and it runs from alt down by itself into the frame and I am guessing back behind driver seat to battery ?
Anyway anyone have any ideas or advice for me .
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Thank you ,, I will open up the wrap that wire is in , it appears to be stand alone and feeds down into the frame and appears I am going to look but appears to go directly back to the battery.
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
The fuse links at starter are ok , the plug on alt has power when key is on to both wires and power to 1 wire with key off .
Main lug wire has no power until alt is spinning , that main wire I understand is direct to the hot side of battery and carries the current to the battery, I am guessing it melted or if there is a fusible link on it it is blown
Main lug wire has no power until alt is spinning , that main wire I understand is direct to the hot side of battery and carries the current to the battery, I am guessing it melted or if there is a fusible link on it it is blown
Le Mans Master
Joined: Oct 2006
Posts: 7,123
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
The fuse links at starter are ok , the plug on alt has power when key is on to both wires and power to 1 wire with key off .
Main lug wire has no power until alt is spinning , that main wire I understand is direct to the hot side of battery and carries the current to the battery, I am guessing it melted or if there is a fusible link on it it is blown
Main lug wire has no power until alt is spinning , that main wire I understand is direct to the hot side of battery and carries the current to the battery, I am guessing it melted or if there is a fusible link on it it is blown
Take a close look at the 6 way connector to the right and behind the distributor- that's the starter extension harness- might have burned a connector in there.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Ahh, ok. That wire from the back of the alternator runs along inside the drivers side of the frame to the battery, there may be a fuse link at the battery end, maybe not. Follow it back from the alternator, its burned along there somewhere
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Six your right , but does anyone know if there is a fusible link on the charge wire from alt back to battery ? I may have to snake a entirely new wire from alt to battery .. grrrrrr on a day it will be in the high nineties
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Burning Brakes
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From: Middleburg Florida
I'd start with a continuity check of the alt. wire to the battery. If it shows open, start following it, I believe there's a fuseable link in that wire, but not sure where. I'd suspect it's under the hood somewhere, but it might be at the battery too. Check it when you find it, just cause it "looks" good....
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 4,000
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From: New York
I have power from wire to where it exits batter area , none up at alt , No fusible link under hood or by battery, I am going to get her up on car ramps and get to the wire that runs down frame and replace it . I am going to put a fusible link up by alt area because I am never going to have to this again !!
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
When I got my 81 there was a splice in the wire about 6" inside the frame back by the battery, couldn't see it until I pulled it out, it was intermittent causing all the electrics to jump. Took me a couple hrs to find it.
