Hi all, Gonna wire in a fan Override switch basically and am wondering about one thing...

I know you take a wire from the earth from the fan switch, but if I want an iluminated switch so I know when its on (blue LED prefferably) do I need to take a feed to illuminate that, if so where from? and how will I get it to work when the fan is on.
Also, should I fuse any of the circuit?

TY please.