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Old 11-30-2009, 01:20 PM
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Gm 3 Wire Hookup

so i know this will be easy for someone, i got this 75 chev truck someone butchered the wires in engine compartment, my question is, the 2 wires that exit the alternator ( in a plug to the alternator ) where do they go? i already got power to the fuse box ( not ALL the wiring was missing ) do they go to the ampere meter in cab? i just dont want to hook up wrong, the truck turns over fine with the key as well allready, ( 2 very short bursts ) and im really close to intial start up, thanks, mike ( also, the one wire from the stud on alternator is already hooked to bat. )

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Old 11-30-2009, 02:40 PM
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Quote:
Originally Posted by diamond mike
so i know this will be easy for someone, i got this 75 chev truck someone butchered the wires in engine compartment, my question is, the 2 wires that exit the alternator ( in a plug to the alternator ) where do they go? i already got power to the fuse box ( not ALL the wiring was missing ) do they go to the ampere meter in cab? i just dont want to hook up wrong, the truck turns over fine with the key as well allready, ( 2 very short bursts ) and im really close to intial start up, thanks, mike ( also, the one wire from the stud on alternator is already hooked to bat. )
The #1 wire (should be brown) goes to the idiot light via the bulkhead connector. The #2 wire (should be red) goes to +12v, either the junction block on the firewall or the threaded post on the back of the alternator. Of course, the threaded post gets the large red wire that goes to the junction block.
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Old 11-30-2009, 08:43 PM
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wires

COOL, i just read some old posts and read yours, im sure i can get it now, that was the LAST ( finnally ) wire i needed to get done
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Old 12-01-2009, 08:30 AM
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Here is a picture for your records.
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Old 12-01-2009, 10:13 AM
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nice! i definitely got this in my files now, thanks, mike
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Old 12-01-2009, 04:58 PM
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smaller wire always to dash guage or light

other wire to hot full time

loop it to the charging post on the back of the alt

will work fine

these are the simplest alts.
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Old 06-14-2010, 08:28 PM
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Are the 12V jumper and indicator light connection optional? Is this really a one wire alternator that has an indicator light output? If the indicator light is not desired, is the jumper still required? Thanks
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Old 06-15-2010, 10:44 AM
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Quote:
Originally Posted by Zeeb
Are the 12V jumper and indicator light connection optional?
If you have a three wire regulator then the jumper wire should be connected.

If you do not have an indicator (charge light) connected then you must place a resistor in series in that line to prevnt "run-on" when the ignition switch is turned off.


Quote:
Originally Posted by Zeeb
Is this really a one wire alternator that has an indicator light output?
No.

The one wire versus the three wire use different internal regulators.


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Originally Posted by Zeeb
If the indicator light is not desired, is the jumper still required? Thanks
Yes. See my reply above concerning the wire that would normally be connected to an indicator light.

If you want a one wire alternator then that is what you should buy.

I prefer and recommend using the three wire system for best overall output and reliability.

Either alternator can have the internal regulator swapped to convert them to the other style.
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Old 06-16-2010, 05:57 AM
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Okay. Now using the indicator light, one side to terminal #1 as shown, the other side of the light to ... 12V? Do I understand correctly that if the alt. were to fail, terminal #1 becomes grounded, thus providing a return for the indicator lamp? Sorry I need the basics here, I'm doing an engine swap (V8 conversion)and have this type alternator on the SBC I bought. I don't have experience with this type alternator (obviously). Thanks.
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Old 06-16-2010, 08:26 AM
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Quote:
Originally Posted by Zeeb
Okay. Now using the indicator light, one side to terminal #1 as shown, the other side of the light to ... 12V? Do I understand correctly that if the alt. were to fail, terminal #1 becomes grounded, thus providing a return for the indicator lamp? Sorry I need the basics here, I'm doing an engine swap (V8 conversion)and have this type alternator on the SBC I bought. I don't have experience with this type alternator (obviously). Thanks.
From #1 terminal on the alternator to one terminal of the indicator light. From the other terminal of the light to the ignition terminal of the ignition switch.
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Old 06-21-2010, 02:03 PM
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Yeah, it grounds on failure. Working you have 12v on both sides of the light=no light. I think there's a resistor in there too (in the dash) If the alternator doesn't output (like just before to turn ign to start) the light goes on as a warning

I know this is an older post but t2 should go as far from the alternator (+) post as possible so it can properly know if you need more alternator output.
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