Hello guys i am putting a 1994 351w into my 1990 f250. I have got all of the wiring swapped, and distributors(along with gears) swapped. Now i am noticing the alternators are different. Also i cant just swap them over because the bracket they mount on are also totally different. Both of the alternators have the same 3-pin plug, but the other 2 plugs are different.

1990 alternator pic- https://www.ford-trucks.com/forums/m...or-153053.html

1994 alternator pic- https://www.ford-trucks.com/forums/m...0&ref=gnr-prev

 

Use the 3G from the 1994.

Forget about the underpowered, fireprone 2G from the '90.

 

When you say you have all the wiring swapped you mean you put the 90 engine harness on the 94 engine but now can't plug in the alternator correct?

If so you need the 3AG regulator plug pigtail with the single pin stator plug pigtail on it to replace the 90's alt harness connector.

Pretty straight forward once you do that.

Middle wire of the regulator connecter will connect to the single pin "stator" connector of the 3g alternator (get that part of the 94 harness it will be plug and play, you'll see what I mean far as that goes)

You'll have cut off the 2g regulator connector splicing in the 3g in its place, that'll give you the single stator with it.

The single post with the nut on it will connect to the positive side of the fender mounted starter relay and with a positive cable coming from the battery on that same post on the relay.

You'll have to circuit match the regulator connector splicing it in place but is a straight forward task, make sure "I" terminal "S" terminal "A" terminal match up 2g to 3g regardless of wire color coding. What I mean is 90 to 94 the wire colors might have changed so double check make sure its correct even if color code matches.

"I" terminal = to the gen light

"S" terminal = simply jumpers over to that single stator plug (Again as mentioned before, pigtail from 94 it'll be all in one arrangement a 3 pin plus 1 connector)

"A" terminal = fuseable link from a 12volt source

I'm wondering if you can release the 94 style stator pigtail/wire out of its three pin regulator connector, release same from the 2g putting the 3g style back in its place negating any need to splice those circuits for regulator complete connector change? Swap out just one wire rather than cut the plug off change to later style?

 

You can use the 2G regulator plug. (they are the same)
Just loop the yellow/white wire to the output stud with a ring terminal, and use an insulated spade connector to bring the white/black wire to the stator plug.

Add a 4Gauge charge cable from the output stud to the battery+ side of the fender mounted solenoid.

Done...

 

Yea figured they where but wasn't positive, release the center pin from the 2g replacing it with the center pin from the 3g it'll be "factory", no third party type spade connector required that way.

The connector is the same safe bet the pins in them are too, release and swap them out.

 

I just suggested he use an insulated spade connector if he didn't want to pony up the stupid money for the difficult to find 'S' connector.
If the OP has both harnesses, by all means, switch the pins out of the plug.

The Motorcraft single terminal locking connector is #WPT852
AKA, Ford #5U2Z-14S411-TA
It's also used for the air conditioning clutch.

 

Oh yea agree, if doesn't have the 94 harness anymore or its damaged an insulated spade connector will work just fine not worth hunting down a stock style connector.

I mentioned it as it sounds like he might have it from doing the engine harness swap, that part simply conjecture on my part too as didn't actually say that.

 

OK, so I went over to the parts truck and found the wire that has the 3pin connector, and the spade connector. There is a green wire that comes off of the main wire about 5 inches befor it connects to the solenoid. Is this just a ground wire? Since the truck, and the wire I'm using have different connetors for this "ground" \ green wire can I just cut both connectors off and splice them together? Thanks for all the feedback,
Ryan

 

What do you mean "main wire"?
The charge cable?
Does this green wire have a rubber tab at the end?
If so, it is a fusible link.


The green/red wire in the regulator plug supplies exicter power to the alternator through the battery light in the dash.
The alternator will not charge without power in run through this wire.

Sorry, I don't have a picture of the '94 wiring diagram in front of me.

 

So can I just cut the connector off of this green wire, coming off of the charge cable, and put the connector off of the old charge cable so this green wire will be able to connect to the truck?
Thanks, Ryan

 

Sorry if im being confusing.. i found a picture and i pointed towards the wire i am talking about.. on my wire it has a different connector than the truck.. can i swap connectors?

pic-https://www.ford-trucks.com/forums/members/1990-f250-706211-albums-1990+f250+engine+swap-42692-picture-alternator-cable-153088.html\

thanks,
Ryan

 

I'm sorry.
I can't open the link, and I'm still looking for a '94 charging schematic/

You are talking about the truck end of the charge cable?
You have the -singular- heavy gauge charge cable from the '94?
It should just bolt to the fender mounted solenoid, unless you have a power distribution box there.

 

 

Thanks Ian!

I see now the fusible links are outboard of the green 'tag' in question.
The wire you point to needs to be connected to the charge indicator.
If 1990-f250 has the correct end I'm sure he could just solder it on.

 

Ok . I don't know why the link isn't working, you can see the pic if you go to my album ..