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Old Mar 12, 2017 | 08:36 PM
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ok i'm in process with a fox body ls swap..i bought a 1 wire kit off ebay (plug, resistor, and shrink tube)..soldered the resistor to a wire end attached to power lug on alt..i havent had this car running at all....so today i was doing some un-related wiring and a 40amp main fuse blew? i know i didnt arc anything or short anything out....so to continue working and testing somethings..i put a 30 amp fuse in the place of the 40...within about 5 minutes i hear a real faint buzzing sound...so i follow the sound right to alt...i felt the alt and it was kinda humming slightly and the 1-wire from plug to power lug was hot!!..i unplugged the plastic plugin and it stopped buzzing.....this is a known good alt i removed from my pickup..anyone have any experience like this? i have done a few 1 wires before on older gm alts..whats going on here? what am i missing? thanks in advance!!
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Old Mar 13, 2017 | 09:13 AM
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Little confused about your setup. The way a one wire setup should work is the resistor is soldered into the (about) 16 gauge wire going from the plastic plug on the side of the alternator to the power lug. This is the exciter wire which starts the alternator charging as soon as it starts turning. Your heavy wire (about #8) goes from the power lug on the alternator to the solenoid on the starter or fuse panel or main power lug nut. This wire is hot all the time. If this is the way you have it wired take the alternator and have it tested.
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Old Mar 13, 2017 | 12:44 PM
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yes sorry i should have been more detailed..yes i have large power lug going to a solenoid and the exciter wire with a resistor...so yea i know this alt was good..i pulled it off my truck as i thought the bearing was bad (it wasnt)...but it has not been used in 2 months?..so idk..never had this happen before..it definitely is a big drawn..it probaly went bad...anyone has the small body alt. part number? thanks!!
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Old Mar 13, 2017 | 01:16 PM
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Default one wire alt

Go to Rock Auto and look thru the list until you find a good cheap unit that will meet your demands.
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Old Mar 13, 2017 | 01:20 PM
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Depending on how much power you need, there is a Toyota Forklift alternator that is a one wire and really small..
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Old Mar 13, 2017 | 01:20 PM
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its the size that i need to worry about the larger alt hits my hood (i have a spare ) the one i have now was on my 07 classic 2500 it has a smaller body that clears my hood...i ordered another one for my truck thinking i would get same alt that came off of it, but it was the larger bodied alt...i think the camaro alt.s might be smaller.. thx!
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Old Mar 13, 2017 | 01:23 PM
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i will eventually have ac but no killer stereo's...3 cooling fans!...this forklift alt bolt right on to stock truck acc's? any idea of amp's thanks for the idea!!
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Old Mar 13, 2017 | 06:20 PM
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From: Little Austin
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The 105 amp truck alternator is smaller than the 130 amp. I can't really say by how much, but there is a difference.

Andrew
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Old Mar 13, 2017 | 06:34 PM
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My one wire alternator exciter wire is hooked to a switched 12v other wise it's feeding 12v to it all the time and not just when it's running. It's going to depend on alternator type, I called my local starter/alternator rebuild shop and he looked it up for my particular alternator and told me what I needed to do.
Edit: Fixed picture to show how mine runs.



Last edited by LLLosingit; Mar 13, 2017 at 06:44 PM.
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Old Mar 13, 2017 | 07:21 PM
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ok that makes sense the 105 is slightly smaller..not much but enough to clear my mustang hood...
losingit interesting what your saying, it makes sense but i have never wired one like that...this has never come up before (in my world lol) i have 3 vehicles wired with exciter straight to big power lug..never a problem and they have been that way for many many years..in fact only one even has a resistor...i have been told it will give you a dead battery but i can let them sit for months at a time and they fire right up....
hmmmm i might wire it like you have said..let me stew on that for a little bit... i appreciate the info thats why we post stuff!!
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Old Mar 13, 2017 | 07:51 PM
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I need to get this done on my truck alternator. Which terminal wire on the alternator plug does the exciter wire from the start signal terminate to?
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Old Mar 13, 2017 | 08:01 PM
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Originally Posted by learning91
ok that makes sense the 105 is slightly smaller..not much but enough to clear my mustang hood...
losingit interesting what your saying, it makes sense but i have never wired one like that...this has never come up before (in my world lol) i have 3 vehicles wired with exciter straight to big power lug..never a problem and they have been that way for many many years..in fact only one even has a resistor...i have been told it will give you a dead battery but i can let them sit for months at a time and they fire right up....
hmmmm i might wire it like you have said..let me stew on that for a little bit... i appreciate the info thats why we post stuff!!
How it's wired depends on the internal regulator that a particular alternator has, They are not all the same and not wired the same, Like I said I called a local shop that has been in the business for decades and even he couldn't tell me until he found out what regulator it had.
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Old Mar 13, 2017 | 09:42 PM
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From: Little Austin
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Originally Posted by Taxman20
I need to get this done on my truck alternator. Which terminal wire on the alternator plug does the exciter wire from the start signal terminate to?
The L terminal. You should also wire the S terminal to the main power distribution point.

Andrew
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Old Mar 13, 2017 | 10:10 PM
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yea thinking on this i will wire the exciter wire to a switched power source..now that being said..wired this way when you first start the vehicle do you still need to rev the rpms past say 1500 rpms to get alt charging? i do have to do that on my other alts that are wired with excite wire to power lug..otherwise they dont charge until they hit that rpm? just wondering??
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Old Mar 14, 2017 | 07:24 AM
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From: Little Austin
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Originally Posted by learning91
yea thinking on this i will wire the exciter wire to a switched power source..now that being said..wired this way when you first start the vehicle do you still need to rev the rpms past say 1500 rpms to get alt charging? i do have to do that on my other alts that are wired with excite wire to power lug..otherwise they dont charge until they hit that rpm? just wondering??
The L terminal needs to go through the charge lamp or have a resistor wired in to reduce voltage. If you do everything correctly you will get over 14 volts right away. No revving required.

Andrew
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Old Mar 14, 2017 | 07:26 AM
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Thanks Andrew. And sorry if I missed it but what size resistor goes in the excite wire? Ive also heard a small bulb works too just not sure what kind.
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Old Mar 14, 2017 | 08:26 AM
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From: Little Austin
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I just buy this...it has the resistor already installed. You can also add another wire to that plug for the S terminal. The terminals are Metripac 150 series.

https://holley.com/products/accessor.../parts/197-400

Andrew
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Old Mar 14, 2017 | 04:10 PM
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The L terminal needs to go through the charge lamp or have a resistor wired in to reduce voltage. If you do everything correctly you will get over 14 volts right away. No revving required
ok I had always thought the resistor was installed to prevent voltage feedback so when u shut off ignition the car wouldn't keep running? i'm feeling really old!!
I know see why the way I had it on my mustang wont work as it did on my other cars..those don't have large power lug on alt going directly to battery...so its looking like 1 wire alt isn't the setup I need..
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Old Mar 14, 2017 | 05:56 PM
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ok i researched the resistor part in this setup it protects the regulator from a direct 12v if you are not using an alt. light. so all i need is L with the resistor to a 12v switched source and if i want the alt to be load sensing i need S hooked to a main power block...ok i think i may have this !!! lol...if this is correct..i would like to thank all involved..for being patient!!!
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Old Mar 14, 2017 | 07:02 PM
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From: Little Austin
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Originally Posted by learning91
ok i researched the resistor part in this setup it protects the regulator from a direct 12v if you are not using an alt. light. so all i need is L with the resistor to a 12v switched source and if i want the alt to be load sensing i need S hooked to a main power block...ok i think i may have this !!! lol...if this is correct..i would like to thank all involved..for being patient!!!
Correct. The P terminal is optional, but I've found that the charging system works better with it connected to the main power distribution point.

Andrew
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