Is this? The photo is 3-pin, but it works for the case knowing that you cannot obtain a tachometer output
Here is a more detailed explanation, although in English:
https://smithcoelectric.com/blogs/tech/common-10si-12si-15si- 17si-21si-22si-wiring-diagram
Basically, pin R is to connect the charge indicator light and F is the field connection to direct positive.