FJ40 Alternator upgrade help (1 Viewer)

[Charliemurphy]

After reading through the posts with @FJ40Jim and @Coolerman discussing alternator upgrades, Im working on upgrading my non functional ‘76 externally regulated 40A alternator and voltage regulator with the FJ62 80 IR alternator. I came across a guy on Craigslist that said had a used one for $50 that worked. Obviously I grabbed some cash and my old alternator to see if it would fit.
See the side by side picks. Definitely bigger and it fit right in. However now that Im trying to figure out the wiring and my first question is : just what alternator did I get? I dont think its a FJ62 Alternator. I think it might be a Hitachi. Any ideas?

Oh, and if any feels like commenting on what the heck Im supposed to do next with the wiring and save me a month of head scratching it would be much appreciated, even worth a cold 6-pack if you’re ever passing through the Denver area. I've got two wires in a socket, 1 wire free, and a 4th black wire attached to chassis ground. I'm guessing the white with blue stripe wire is going to the battery and the other two are ignition and the charge light (which I don't have anymore , apparently (Thanks PO!) So where should I start? I've been looking at the FJ40 1976 engine wiring diagram and the 1980 FJ40 wiring diagram side by side to see when the changes were made. I think I'm missing the electronics gene.

 

[Coolerman]

A model # of the Hitachi alternator would help to verify exactly what you have but I believe it will work. Post the model # so I can look it up...

First thing you have to know: Your old alternator had a regulator. The new one does not require it, so some wiring changes have to be made. The new alternator requires the following connections:

1. A switched +12V wire commonly know as the exciter wire.
2. A charge wire to the alternator B+ terminal
3. Ground

The 10ga White/Blue wire with the ring terminal from your old alternator hookup connects to the B+ terminal on the new alternator. This is the charge wire.
The alternator will ground itself through the mounting bracket.

That leaves the switched +12V exciter wire. Here is how to get that easily.
First you need to order the following parts from me: Part# 3P8862W and Part #Jumper1.

The first part# is the connector that will plug into the back of the alternator. It has two wires in it. A BY wire which will splice into the new +12V exciter wire (read below) and a yellow wire that can be used to hookup a charge lamp if you want it.

The second part is a connector with a simple jumper that will plug into your old three pin regulator connector coming out of the harness and will use the +12V wire there and jumper it to the White Green wire that already goes from the regulator area to the alternator. This Green/White wire will be your new +12V exciter wire.

Once you install that jumper plug, you will cut the black three pin connector off the old alternator plug and splice the White/Green wire to the Black/Yellow wire on the new alternator connector. The White/Black wire from the old alternator harness will not be used and can be taped off.

If your regulator has a different connector other than a three pin, I would need to see a pic of it to get you the proper jumper connector.

 

[Charliemurphy]

Thanks @Coolerman , I will be rereading your instructions several times to get it but I think I can get a little forward movement. And I'll be ordering those parts from you!