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LS1 alternator on LS2 Engine

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Old Jul 9, 2011 | 06:03 AM
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Default LS1 alternator on LS2 Engine

Long story short I have a 05 GTO LS2 engine in my car. Because a friends alternator died I gave him my LS2 alternator with bracket and everything and he gave me his LS1 bracket and ordered my a new one.

The thing now is I've got some damn problems hooking up this alternator. It just doesnt seem to charge...

On the LS2 harness side I have a orange and a grey cable going to the alternator.

On the alternator side I have four wires blue green yellow white.

The vendor of the alternator told me to hook up yellow to gray and thats all it takes. But after 20 minutes of driving the car started stutterin and I barely limped it home. Battery was completly dead and after recharging it I found that the alternator doesnt charge the battery.

Without the car running none of the GTO wires carry a +12V signal. I haven't checked running yet because the battery is still charging.

The alternator I have is for a 98-02 Camaro with these numbers:
Delco 10480308, 342, 343



Anybody can tell me what wires to hook up?

Thanks
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Old Jul 9, 2011 | 06:37 AM
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I don't know the color pin outs on a GTO, but can say that you need an exciter wire to one of the alternator pins. With "key on" it sends battery voltage to the alternator. Sounds like that's what the yellow wire is supposed to carry 12v. On my alternator 12v enters the alternator @ the first pin. I've assumed that the heavy gauge high current wire has also been connected to the back of the alternator.
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Old Jul 9, 2011 | 06:52 AM
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Yeah the heavy gauge wire that runs from the alternator to the starter, to the battery and so on is connected.

The thing is if I remember right the GTO LS2 PCM runs the alternator through a duty cycle signal so I wont get a straight 12V from one of the current wires.

If I just take a 12V signal from somewhere else do I need a resistor?
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Old Jul 9, 2011 | 08:31 AM
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Just checked when the car is running.

I get a 5V signal from the grey one and nothing from the orange one.
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Old Jul 9, 2011 | 10:24 AM
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Originally Posted by D3xt3r
Just checked when the car is running.

I get a 5V signal from the grey one and nothing from the orange one.

Yah, I meant voltage from the exciter source. If you do a search in the external engine section, there's probably a schematic or a better description in there. Sorry, that's all I know. On mine, the exciter wire from the PCM connects to the first pin & that's it.
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Old Jul 9, 2011 | 10:44 AM
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Got it!

Grey wire that carries 5V signal to the L signed pin at the alternator and dang I've got 14.6V.
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Old Jul 9, 2011 | 08:27 PM
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Glad you found it!
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Old May 19, 2014 | 09:26 AM
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I know this is an old post, but it's *exactly* what I'm trying to do. The trouble is, I can't quite figure out the final outcome from what was said. Was the gray wire from the LS2 harness hooked to the L pin on the F-body alternator, and that's it?

Other than the lead to the battery/starter, this is just a 1-wire connection? Does the orange wire from the LS2 harness just get capped off, along with any other wires coming from the LS1 alternator?
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Old Dec 22, 2014 | 12:25 AM
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Originally Posted by rquad
I know this is an old post, but it's *exactly* what I'm trying to do. The trouble is, I can't quite figure out the final outcome from what was said. Was the gray wire from the LS2 harness hooked to the L pin on the F-body alternator, and that's it?

Other than the lead to the battery/starter, this is just a 1-wire connection? Does the orange wire from the LS2 harness just get capped off, along with any other wires coming from the LS1 alternator?

Bump,wondering the same thing.
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Old Dec 22, 2014 | 06:12 AM
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Default Easy

Just hook the Orange wire to cavity B and the Gray wire to cavity C. The alternator will work as it should.

Bill
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