Appears mechanics level 7 (or possibly 8 as i have a +1 boost to my normal) works (just conveniently got to upgrade myself while standing in front of it, and had the same issue where it seemed that would be the ideal spot for a switch, but nothing was lit, then when leveling up, it turned purple in the center). My main character's perception is 15, and a couple others have 18; I'm still quite the novice, so hopefully not messing up this feedback too badly.