[Gerk]

I just swapped 3.9l from a 1990 Classic into an 89 classic.
The wiring is just a bit different between the 2.
Can anyone help with what wires go where?

Big brown goes to the nutted terminal
I have a small brown (from the harness), a small green(out of the alt), and a broken white one(from the harness)

 

[Gerk]

I am just bumping this up hoping to get a quick answer.

thanks for helping if you can

 

[RRLondon]

Unsure of specifics on your vehicle, but they usually go something like this; as you've got, main out brown to deliver power to system from alt, small brown is ignition switch controlled supply from battery (this switches on the alt to make the field windings produce power) so you should see this go live when key is turned to position one.
The others, I think are green to ignition light on dash to indicate charging state, and the white from loom could be signal wire to rev-counter as it takes a pulse signal to read for revs (if counter is fitted).

Hope that's some help.

 

[Gerk]

Yeah that helps.
I had a friend over and he said this (which I am unsure about) What do you think?

Small brown connects to the green wire
White goes to the terminal shown in pic

I don't want to screw something up and electrical is prob not my strong suit

 

[JS5D]

There are fundamentally 4 connections:

1) Ground - body
2) Power out (heavy guage wire 40-100A)
3) Voltage reference. can be connected to the power out, but better connected direct to the +12v battery terminal (see detail below)
4) Alt indicator wire (dash bulb). This will let you know the alternator is working, but if the bulb is gone (or you install an LED) there will be no field current and the alterntor will not provide power.

The alternator will regulate the output to 13.4v or thereabout, but since there will be voltage drop between the alternator and the battery (through the heavy gauge wire) the alternator should actually provide more voltage under load. The voltage reference cable allows the alternator to 'know' the battery voltage regardless of load and up the voltage accordingly. If you connect the reference voltage to the alternator power out it will use give a constant voltage and the battery will see less voltage under load.

 

[KK88RRC]

Big brown... battery... goes on the big nutted terminal
Little brown/yellow trace.... battery light... goes on small nutted terminal
White wire... tach... goes on spade terminal but connects also with blue or green wires (sorry my pic does not show how they connect)

 

[Gerk]

Thank you all for the help. Think I got that part all figured out