Wiring Question - Ford Big Case Mitsubishi Alternator Retrofit

[Will Van]

I am going to retrofit a Ford Mitsubishi 215 amp alternator to my '93 80 series chassis. The advantage of these alternators is they are internally regulated (like the OEM Toyota), are readily available, and easily produce 215 amps. For the purposes of this discussion, I've got the physical mounting solved. But can anyone help me with the wiring portion?

The stock OEM Toyota alternator is a three-prong unit:

• The "L" pin is for the idiot "L"ight

• The "IG" pin is hot with the "IG"nition on. It must have power with the key on or the alternator will not work

• The "S" pin "S"enses the voltage and adjusts output.

And here is the Ford 3G alternator. Also a three-prong unit

• The "A" pin always has power to it through the B terminal.

• The "I" pin is wired to the ignition.

• The "S" pin goes to the stator plug at the back of the Ford alternator.

• The ignition wires on the Toyota harness and Ford alternator are obvious and can just swap them over.

• It looks like the "S" Pin on the Toyota is the same thing as the "S" pin on the Ford - regulating voltage.

• The "A" pin on the Ford alternator always has power to it, but I’m not sure what it is for.

Edit: The only connection I’m confident about is the ignition. The respective “S”, “L”, and “A” pins I am unsure of.


Basically, how do I wire this thing?

 

[Will Van]

I’ve done a little more research. It looks like the Ford 215 amp alternator is a Mitsubishi unit, and it comes with a slightly different wiring design than the regular 3G units. There is no stator plug built into the alternator like in the photo in my original post. Just a “B” terminal, a ground terminal, and a regular 3-wire plug.

So maybe the “S” pin on the Ford/Mitsubishi is also to control charging? Does anyone know if the stator is related to sensing voltage or adjusting the output of the alternator?

 

[Will Van]

I found this diagram to wire the Ford 3G alterntor to an ‘85 4Runner.

 

[Rollinns]

Did this work correctly?
Does your dash gauge work?

 

[Will Van]

Did this work correctly?
Does your dash gauge work?

Unfortunately I never finished the install. I sold my 80 and moved to a '77 40 series.