Is there a procedure to test/verify a TruTrak Pictorial Turn & Bank on the ground/bench? (It's not installed in the panel yet.)

I've no reason to suspect that this used unit is broken. I'm able to test the continuity and the stepper motor makes a little warble when it powers up.

Setting the unit on a level table, the 'horizon' matches the wingspan icon. Tilt and hold unit at 45 degrees and the stepper motor adjusts the 'horizon' to match the wingspan icon. Tilt unit back to level and the stepper moves the 'horizon' back to match the wingspan icon. Same for the opposite tilt. (The wingspan icon is fixed on the glass of the instrument. The 'horizon' is rotated by the stepper motor.)

I'm not simulating the G, centripetal, and yaw forces that the sensor would read in a real banking aircraft, so the fact that the unit does not rotate the horizon icon to match my level floor is not altogether surprising, but I'm wondering if the behavior of the display as described is expected.

Are there any other tests that I can do before installing the unit in my panel and going for a test flight?

Secondary question. There are three labeled electrical connections: power, ground, AUX. Does AUX have a function? Is it to illuminate the instrument face?