My memory is hazy as it's been many years, but the two pins of the regulator plug should be marked with a letter each.
I think they are:
L - light - connect to the warning light wire to the cluster.
S - sense - connect to the positive battery terminal.
This is run to the battery directly on the OE vehicles with this regulator, (rather than to a nearby power feed), as it's used by the regulator to determine the actual voltage at the battery, to control charging more accurately than earlier alternators.