79 Ford F8000 3 Wire Alternator wiring help!

[Breithaupts]

Hey gents - Wondering if anyone can help out on how to wire a 79 Ford F8000 Truck that hauls my Garrett 21A.   It's a 3 wire setup and In know the beg red wire goes to battery but there are two smaller wires and I'm not sure where they go?  The new alternator from NAPA (cough cough) did not come with a diagram, and i should have carefully marked the wires... live and learn.  Online help is spotty and there's nothing specific to my model.  Wondering if there's anyone that can help out, or at least steer me in the right direction.   Thank so much -  Love the forestry forum.  I'm a newbie  8)

[red]

What color are the other two wires ?

[bushmechanic]

Usually one is for the field coil and the other one is for the tachometer. What is the make of the alternator to be sure?

[pineywoods]

It's been a long time ago, but seems to me all 3 wires went to an external voltage regulator. I have an f150 about that age stored in my barn. I'll try to remember to take a look, should be the same or close.

[dgdrls]

http://www.junkyardgenius.com/charging/ford02.html


diagram for External regulated, if the alternator has a ground, use a connector and ground to the
same ground as the external regulator, it keeps your ground(s) common.

D

[mike_belben]

First need to identify the alternator.   On a delco youd have one lug to charge battery, a ground from the case, a blade terminal for exciting the field (lightbulb in series from switched ignition source) and one blade terminal for the sensing wire.. It goes wherever the largest voltage drop in the system is on positive side but anywhere will work.