Alternator wiring for 12HT (1 Viewer)

[panoramic]

Folks,
I am lost on this one because I did not begin with an assembled alternator. I have a 12HT and a freshly rebuilt alternator that I believe is designed for an internal regulator. The alternator had no tag on it to identify it further. I have a regulator that mechanically fits exactly over the two posts and three terminals, but I have NO wiring information for this! The three wires coming from the cable are as pictured: Red, White, Blue. The engine came from a HJ-61 donor.

I am trying to figure out which wire goes where and what are the connections - besides the big 'B+'

Is there a small diagram of the alternator wiring (w/ internal regulator) for the 12HT or the HJ60/61'?
Does anyone have the proper pin-assignment for this plug?

The picture below shows the brush holder without the regulator mounted on top. The regulator simply piggy-backs to the brush holder and has spades that overlap all of the brush holder's 3 small terminals.

FWIW: I am trying to graft the engine into a FJ40 that also had an internal regulator. The 2F alternator had a 2-wire cable for ignition and voltage sensing. I do not know if I have the right plug on my alternator! Since I have never seen the correct wiring I am really in the dark here.

Thanks for any help,
Eric

 

[Henry James the 47th]

According to the 12HT/2H Engine FSM, for HJ60, 61 series with IC regulator, there are 4 terminals on the alternator:

'S'

'L'

'IG'

'B'

now, 'S' and 'B' are split off from the same originating wire, which goes back to the fusible link on your battery. This is a main power feed then.

'IG' on the alternator originates with the Ignition Main Relay, terminal 4, and on the way to the alternator/regulator branches off to the Charge light relay (and through the 'Charge Warning light"), terminals 2 & 3 on the Charge Light Relay. From terminal 4 on that relay, a wire runs to the alternator terminal 'L', passing through a 7.5a fuse "Charge".

The 'IG' terminal on your ignition switch goes directly to terminal 3 on the Ignition Main relay. Terminal 1 on that relay (same side as terminal 4) goes to ground, and terminal 2 on that relay (same side as 3) is a wire split off from the line going from the fusible link at the battery to 'B' on the alternator. So, in summary, the power wire from the fusible link at the battery has two wires forking off it on its way to the alternator 'B' terminal; one wire goes to Ignition Main relay terminal 2, and the other connects to the alternator at 'S'.

When the Ignition Main relay receives current from the ignition switch (again, terminal 'IG' on the ignition), the relay opens, directly routing the power wire at terminal 2 through to terminal 4 on the relay, which then supplies the Charge Light Relay and Charge light lamp, emerging from the Charge Light relay at terminal 4, from where it goes through a 7.5a fuse and connects to 'L' on the alternator.

Hope this is of some help my friend.



Sorry about the lack of a picture -my scanner has gone down for the count.

 

[panoramic]

OK,
I have gotten more data sheets so I will post them up here for everyones benefit. I pulled some from the HJ60/61 FSM and a few from an aftermarket regulator company.

What was also interesting is the cross-reference sheet of regulators. I need to post that on the part number section.

I also learned that the alternator has more than just the bridge diodes - There is a 'trio'. This is used to kick-start the field excitement during low-rpm startup.

Now I need to find the female connector for the alternator cable, sort out all of the pictures and make an adapter plug for my FJ-40 alternator connector. I also need to find out the specifics of the charge light relay and either find one used or make one ...

 

[pjohnson]

Do you have a build thread going? Got pics of the progression of teh swap?

I will be doing a similar swap and would be interested to hear (and see) what you've done.

Thanks,
Phil

 

[Mountain Goat]

I've been through this one. What a PITA!

I don't recall right now what diagrams I kept, but if you have specific questions I may be able to answer.

On my project I used an alt from G&S Cruiserparts. They started with a 24V 12H-T alt, smashed it together with a 12V 3B alt, and came up with something that fit and worked. I had to cut the connectors from the harness and alt and crimp on my own.

I can get pics if you want.



Oh, BTW - Don't use the diagrams in the Aussie Haynes manual for this truck. They are incorrect (at least for my engine).

 

[Inventure]

I have searched high and low and this thread is the closest I can get to finding out how to wire my 2H internally regulated alternator.

I am trying to wire the alternator in to fit with a wiring harness from a 1976 FJ45, which had an externally regulated alternator. The problem is it was not a standard alternator in the FJ (had a 307 V8 with a Bosch alternator fitted) so I think that the alternator wiring has been modified also.

SO, if I build the loom section myself, then using the above diagram, the B wire from alternator is the B+ pole on the alternator, then there are the other 3 wires, blue, pink and white. What does each colour join in to in the diagram?

Can someone match the colours white pink and blue to the wires S, L and IG please.

 

[Inventure]

I really need some help with this. Any help anybody?

 

[NathanX4]

Hi Inventure
I'm new to the forum and from south africa. I am currently struggling with the same problem. I know its been years but i was wondering if you can share what wire is what.

Pink
Blue
White
???

 

[panoramic]

I hadn't logged in in several YEARS because of a nasty divorce and custody litigation. I am BACK!!!!

Your questions don't really belong in this thread though - because you are not fitting the same alternator.

What you need is to start a thread and identify the alternator you are using with the EXACT P/N and what application it is from. Then we can find the real diagram.

Best,
Eric

 

[NathanX4]

I'm not sure of the alternator but it looks exactly the same and the plug is also correct.
Its on a toyota 2lte engine

 

[NathanX4]

Last night i took it out to have a look
Its a toyota denso
There is no marks on the regulator.