Here’s a short vid of the “illuminated” switches I made for my Modular… I even installed a brightness control.
Those Hi-Brightness LED’s are pretty blinding when you’re right on axis… 
https://www.youtube.com/watch?v=Bz3SpQO8RkU
Cheeerz,
Tom
Superb job there Tom..I attempted this a while ago but it got very messy. My method was to dismantle the slide switch , make a silicone mould of the plastic switch slide and cast up using clear resin. I have a VAC tank so this was pretty easy. But the insertion of the led made the resin too brittle, they always split.
So I simply cast them in coloured resin I.e. white/red/green. But no gay lights!!
So on the original modulars switch up…was on? Jeez that one went straight passed me.!