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Topic: OOPS ... ALT hep

in Forum: C3 Electrical

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OOPS ... ALT hep (1/7)
6/20/12 12:34pm

tonytheroofer
Former Member
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

Was working on car , slipped and shorted the red wire on back of alt sparks flew !! So i finish up and start car and Alt light is on and gauge shows 12v .. I think damn I fried the regulator .. So i pull alt today , they testi t say it is ok so I toss it back in car and same deal, alt light on gauge at 12v

So I go back and I get a new one which they test before I buy it tests good . I put it in and get same result light is on gauge shows 12v. I go under car with volt meter and test fusable links at starter , I test both sides and have power on each side of the links. So whats is the deal ? Anyone have any ideas ? All fuses are good as well not that I expected to see a charging fuse lol..

1 more thing with car off I have no power to the main stud on back of alt , however if I start the car I get plenty of juice off that main red wire that bolts to the rear of alt. Should I not have power to that wire even with the car off ?

Any help is always , appreciated !!!!!!!!!!!!!!!!

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

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Re: OOPS ... ALT hep (2/7)
6/20/12 12:46pm

Adams' Apple

Lifetime Member
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Duncanville, TX - USA

Vette(s):
#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
Posts: 20129

My bet is you fried the fuse link. The red wire at the alt should ALWAYS have battery voltage. There are a couple of fuse links down by the starter, in the harness. You need to check for battery voltage on BOTH sides of the links. If you find on that only has voltage on the starter side, that's your culprit. Some cars will also have fuse links in the harness that runs behind the distributor, and also on the driver side fenderwell, connected to the junction block there.

Here's a couple examples of what fuse links look like...

https://www.c3vr.com/member_pages/4401_4500/4427/fuselnk.JPG

https://www.c3vr.com/member_pages/4401_4500/4427/fuselnk2.JPG

______________

Joel Adams
C3VR Lifetime Member #56
My Link

(click for Texas-sized view!) NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

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Re: OOPS ... ALT hep (3/7)
6/20/12 4:06pm

tonytheroofer
Former Member
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

Thanks ! I tested ones down at starter and had voltage on both sides of the link ( There are 2 of them down there ) One has dual wires going into it the other a single wire

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

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Re: OOPS ... ALT hep (4/7)
6/20/12 6:23pm

tonytheroofer
Former Member
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

Ok here is where I am at .

I pull plug on alt test with key on and have good power at plug on both connectors . BUT the main lug on back of alt has NO power until I start the car , I always understood that main power lug had direct battery voltage so even with car off that heavy wire had battery voltage.

So i ran a jumper from the hot side of battery to that rear alt lug , when I did that teh light went off on dash and the gauge pushed up above 13v . So it appears that main lead has an issue does anyone have info or a diagram of that main power lead ..

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

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Re: OOPS ... ALT hep (5/7)
6/20/12 10:15pm

tb2k82ce

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Lemon Grove, CA - USA

Vette(s):
1982 C3 Collectors Edition 44000 miles, sat in the sun most of its life, My wife purchased it for me for Father's Day in 2007 from her girlfriend that had it for 19 years. It is on the road again. I'm retired but it is now my daily driver.

Joined: 10/17/2007
Posts: 2041

Tony PM me your email and I will send you three pages from my 82 Corvette GM service Manual. Your system should be the same I'm guessing. Or you can just update your profile to include your email and I can do it then.

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Re: OOPS ... ALT hep (6/7)
6/20/12 10:53pm

tonytheroofer
Former Member
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

thanks ,,, diehrd9@yahoo.com

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

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Re: OOPS ... ALT hep (7/7)
6/21/12 9:39pm

tonytheroofer
Former Member
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Rochester, NY - USA

Vette(s):
1980 L- 82 fully restored and upgraded.

Joined: 6/12/2012
Posts: 95

Well that was fun ... NOT .... It was the main wire battery to alt that had cooked . It is snaked through the frame I could not get it out and had to neatly zip tie new cable in along frame what a pita ... THANKS FOR all the help people !!!!!!!!!!!

______________
1980 , ZZ430 , 3.92 rear , 700R4 2400 stall NEW EZ EFI

https://www.c3vr.com/member_uploads/16001_16100/16019/resized201331973928r.jpg

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