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[GMCnet] blown fuses: alternator saga, continues... [message #303664] Sat, 16 July 2016 16:48 Go to next message
Ek_Lektro is currently offline  Ek_Lektro   United States
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Registered: March 2011
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Senior Member
OK, might’ve found the problem here! (and learned a bit about alternators)
Last December we were so caught up with Birchhaven stuff,
we had a local pickup mechanic (AutoZone parking lot mechanic) do the Eleganza alternator swap for us.
So... when we needed to swap it again, ourselves, last month, we just mimicked the way they had it hooked up.
Well, today Jim B tells me that the wires had been reversed all along!

the way we had it hooked up:
thinner black wire to terminal 2 (top)
larger red wire to terminal 1 (bottom)
start it up and alternator gives 16 to 16.5 volts

the way its supposed to be hooked up:
larger red wire to terminal 2 (top)
thinner black wire to terminal 1 (bottom)
.. but now the alternator gives low voltage… 3.5 volts.
So it sounds like we’ve found the problem.. and gotta swap it again (here at the beach)? (brought a spare)

Before we rip into that job, Does that sound like “normal” behavior for reversed wires,…
alternator charges… but overcharging?
And with wires brought back to normal, very low voltage = “blown” alternator?
Wrenches at the ready, seeking confirmation ….

Oh, the agony and ecstasy of life with 2 GMCs :) (changing alternators at the beach)
Thanks everbody; Ken, Jim and Jim…
cheers,
Greg

> 14.5 is the high end of normal. 17 will hurt stuff long term. You should
> only see that immediately after startup or heavy battery drain. Check the
> two conductors that exite the slip rings. If loose, bad ju ju.
> Jim Hupy

>> alternator (Autozone Duralast 100amp installed just
>> this past december) was putting out 16 volts?
>> soon started creeping up to 17 volts.. so eventually we blew a headlight.
>> Then last month, repeatedly blew the turn signal fuse, so we replaced the
>> alt under lifetime warranty,

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Re: [GMCnet] blown fuses: alternator saga, continues... [message #303671 is a reply to message #303664] Sat, 16 July 2016 18:58 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Registered: October 2006
Location: Woodstock, IL
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What I'm not following is there is the output terminal lug and then the other 2 wires are in a 2 pin connector that should only go one way so the locking tab works. Did he de-pin the connector or force it in backwards?

John Lebetski
Woodstock, IL
77 Eleganza II
Re: [GMCnet] blown fuses: alternator saga, continues... [message #303673 is a reply to message #303671] Sat, 16 July 2016 19:23 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Yes.
On Jul 16, 2016 4:59 PM, "John R. Lebetski" wrote:

> What I'm not following is there is the output terminal lug and then the
> other 2 wires are in a 2 pin connector that should only go one way so the
> locking tab works. Did he de-pin the connector or force it in backwards?
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
> Source America First
>
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Re: [GMCnet] blown fuses: alternator saga, continues... [message #303742 is a reply to message #303664] Sun, 17 July 2016 23:40 Go to previous message
Ken Burton is currently offline  Ken Burton   United States
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Registered: January 2004
Location: Hebron, Indiana
Karma: 10
Senior Member
It sounds like you now have it hooked up correctly and the start lead is not working. I believe the start lead circuit goes through the "gen" light bulb on the dash.

Does the "Gen" light work? If not, then try replacing the bulb.


Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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