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ka620'

L16 charging problem

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On some of the external regulated alternator there is an extra spade connection which doesn't get used... make sure the only connections you have are the 2 in the tee connector and main power output....

My light was staying on at first because I had the white wire going to that extra spade, which was wrong ... it gets constant battery power, usually it's connected at the main power input on the starter....

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I do have that white wire T'd off onto the white/red wire that goes to the power for alt. Where is that solid white supposed to be then ?

 

Datzen mike- im not sure my dad did it a couple years back and just left it. Im sure he went down to autozone and got the one for a 620

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The White wire on the regulator joins the White/Red wire from the T connector on the back of the alternator. Together they join the fusible link, and the other end of the link goes to the battery positive terminal. Looks like yours is correct.... so far.

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Am i supposed to be getting ppwer to the yellow wire at L plug or just the white/blk wire?

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No idea. Plug should be

 

Yellow... Black

White.... White/Black

W/Red... W/Blue

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Yeah thats what ive got. Is the yellow wire supposed to give off any voltage ? I have 0 volts to it

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If i knew what the voltage was supposed to be at each wire I would be able to trouble shoot it a little better. Is there any schematic showing what wires get voltage?

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Not that I know of. Take the alternator and the regulator into NAPA and have them tested.

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Got the alt tested twice , passed both times. Do you know how i can test the regulator ? They said they dont test them anymore..

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I think im just going to go for the internally regulated one.. what does it come off of ?

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Forsure , im only getting 12 volts. Im just going to get the internally regulated alt and wire it the way datzen mike said.

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All '78 and up Nissan alternators were internally regulated.

 

The truck is a problem. There is not enough room for the larger diameter 50 amp car alternators. They don't have enough room and don't clear the idler arm just below it. I would get a 38 amp '78 or '79 620 truck alternator. Small and they fit a truck. I have a 2002 Altima 90 amp alternator because there is no clearance problem with a car.

 

Research a 90 amp Saturn alternator and see if it was ever swapped into a 620 or 521. There may be others.

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So since i had already wired it all up back to stock and i was only going to get an extra 5 amp by switching over to internal i figured i would make this work. All of my wiring looks to be correct according to the diagram , but i noticed on the diagram the red/white (power) wire that comes off the alt is mounted on the block side of alt and ground is on the side closest to the fender. On mine it looks to be backwards. Ground is on block side power is on other. So my question is , if i switch them to see if mine is incorrect will i short anything out ?

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I wouldn't try switching them, you will end up putting battery power directly to ground. Yes you will short something out... if it's a newer alternator they dont quite look the same as the old ones.... here's a pic a found for the wiring.

Screenshot_20170710-142447.png

 

As long as these wires are hooked

Up at the alternator you should be good...

I can check something more on my 521 if you need, I am still running the external reg all stick wiring.. I can try to help....

 

So are you seeing only 12volt while running? That sounds like battery voltage and the alternator is not turning on... voltage should increase to around 14 volts... does your charge light come on at all? It should be on when ignition Is on but not running..

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The insulated terminal is the power. The screw or bolt on the alternator case is the ground.

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Forsure .

Yeah my alt isnt turning on. Charge light comes on when i turn the key and after i start the truck it stays on. What does your ground coming off the alt go too ? If you have a test light could you do me a favor and see what wire sees power at the L plug on alt ? Either yellow or white/black.

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The alternator is grounded through the case to the engine block but it  never hurts to have that black ground wire also. It goes to the body ground and also to the negative battery terminal.

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Forsure .

Yeah my alt isnt turning on. Charge light comes on when i turn the key and after i start the truck it stays on. What does your ground coming off the alt go too ? If you have a test light could you do me a favor and see what wire sees power at the L plug on alt ? Either yellow or white/black.

I'll check thst later this afternoon when I'm working on mine...

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Screenshot_20170711-064814.png

I couldn't find a better wiring pic... ignore the red loops at the regulator...

But by this pick the yellow is power coming from the regulator, the white and black is the output for the charge light. The other thing is check for ignition power on the the white and blue wire on the regulator.... make sure that's turning on too....

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So here is what each of the wires are doing.... sorry no diagram but the diagram above shows the wires, so I'll do the best I can to describe.... and in no particular order... and I'm saying 12v regardless.. yes while running is should jump up to 14.4.. anyhow...

First the regularor....

Black - ground

White - 12v constant

White/blue - 12v ignition input from key

White/black - 12v ing output to alternator

Yellow - input from alternator

White/red - 12v output to charge light..

 

Alternator...

Main Power output and ground

White/black - 12v ignition from regulator

Yellow - was showing ground while not running, then was outputting a signal while running...

I was using a computer safe testlight, just checking power/ground not an actual volt meter, so the yellow wire is the only one I'm not sure about what it's actually outputting for a signal....

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I don't know if you can trouble shoot by measuring voltage on each wire. IF it is wired correctly it's either the alternator or the regulator. These can be tested at places like NAPA. 

 

A new internally regulated alternator would replace both.

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