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Old 09-05-2017, 06:40 PM   #1
cris well
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1 year old alternator went out--New one barely charging above the red

It's a 1993 Sierra with 350 and auto trans.

The truck has mainly been sitting for the last year.

Last weekend the 1 year old alt stopped charging so I returned it for another one from O'reilly.

The new one is charging just above the red mark on the gauge.

Is this OK or normal? It used to always stay right in the middle of the gauge.

Thanks for any help or info.
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Old 09-05-2017, 08:37 PM   #2
Tom
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Re: 1 year old alternator went out--New one barely charging above the red

Forget the gauge, check actual output. At the very least hook up a multimeter to the battery while running.
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Old 09-09-2017, 08:23 PM   #3
cris well
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Re: 1 year old alternator went out--New one barely charging above the red

Thanks Tom.

I checked it at the battery and it was bouncing from around 9 to 11 amps.

I let it run in the yard for about a half-hour and it killed the battery.

I then took the plastic cover off the pass. side firewall where a bunch of wires run in there and bolt onto a block looking thing.

I wiggled one of the wires that goes from red to (gray/green maybe?) can't really tell with a white round wire splicer-looking-thing.

I think it is the wire that bolts to the stud on the back of the alternator.

Anyway it started charging at 14 amps and the alternator started making a noise like a big draw was on it.

Wiggled it a few more times but couldn't get it to put out 14 again.

Is this common? Do I need to replace the wire end or maybe the whole wire?

Thanks again for any info.
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Old 09-09-2017, 09:34 PM   #4
Kudzupatch
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Re: 1 year old alternator went out--New one barely charging above the red

Probably need to take each one loose, clean the terminals, check the connections at the terminals and reassemble. Sounds like you have a dirty connection.
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Old 09-11-2017, 02:31 AM   #5
cris well
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Re: 1 year old alternator went out--New one barely charging above the red

I took the one off that is the problem wire and cleaned it but it didn't help.

I wiggled it around some more though and got it to draw again from the alternator and the gauge was charging at 14 amps.

Can I cut the wire back and add a new piece to it or possibly run a whole new wire from the post on the back of the alternator to the block?

Can I go from the back post on the alternator directly to the hot battery cable?

Do I need that white wax-looking fusable-link thing--I'm thinking I probably do need it.

Thanks
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Old 09-12-2017, 10:08 PM   #6
cris well
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Re: 1 year old alternator went out--New one barely charging above the red

I think I got it fixed.

The wire coming from the post on the alternator was broken inside the sheathing about 3 or 4 inches down from the connection at the block on the firewall.

I cut another 8-gauge wire (I think it is) off an old truck with a fusable link in it and pieced it together about 8" down the wire.

Charging fine for now.

Thanks to all for the help.
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