It should only light up when there is a signal going into it. If it doesn't light up then, then there is a problem.
-- snowtires

will test tommorow

-- Broken-Form

I have MI Veils 2020, don't have it patched to anything at the moment but when I move the sliders up, the tip on the sliders do light up...same with the knobs directly above the sliders...if you turn those, the light on the tip of the slider also lights up.

JB