Baldy,
Because of the pin orientation and pin location, I think this unit is an older style external type. My poor notes show that on this style alternator, 'R' terminal is switched voltage and 'F' terminal would be the sense circuit.
I have a SI style in front of me...the case is marked near the DA terminals 1/R--2/F. Why they double mark these things I don't know, but those markings would correspond to my guess on wire function.
EDIT. I think I'm wrong on those terminals. After looking at a few manuals, it seems that Baldy was probably correct. 'R' would be sense and 'F' is switched.
Stuart
