Just use a 9v battery to the white leads.
I will admit, that I got all techy & made up leads so I could wire in the switch and indicator when I tested mine. I will also point out that I'm an Engineer, and my wife recognises that as both a valid career and a known medical condition.
Make a point to watch where the jackscrew exits forward into the elevator spar area, and make sure it doesn't foul on anything.
RV-9, Tail Feathers done, Wings almost done.