Hello Bill and all early Santorins and SMs owners,
the first mainsail furlers (in-mast and out-haul) on Santorins and SMs were made of a Bonfiglioli gear-box driven from a CIMA motor, 12V for Santorin, 24V for SM.
These motors have 4 input wires (black, blue, brown, yellow/green). The blue is the negative (not attached to the solenoid).
The three other ones supply positive for both in and out movements.
The yellow/green wire is definitely NOT a ground wire. DON't connect it to the ground circuit!
If you cannot get the solenoid as original, you can replace them (both) with the two wires solenoids (that equip the later AMEL boats), but the connection is different.
I will try to get the wire arrangement to shift from the first version to the second one as soon when I'm back in France (end of next week).