Yes I am very familiar with Trombetta products, there contactors are top notch.
But that type of solenoid is industrial application,not power sports or automotive.
And where would the 3v, with the needed amperage to pull in the plunger, come from? Certainty not the ecu or speedo cluster. Plus its only a 2 wire set up. No 3rd wire tap. Also the wire diagram posted above shows 12v to the relay feeding the solenoid, and an ecu ground, nothing else.The ecu ground probably lets the relay only pull in when the ecu determines its safe for the diff to unlock/lock, probably that means stopped.
Again we can put this all to rest with a simple reading of the sticker.
My bet is its 12v only.Thats what I can read on it. Everything after the 12v looks like maybe serial numbers to me. My old eyes can't see 3v any where, but with the angle its hard for me to read it.
Come on Dmax, post it up....