If you mean that it doesn't light up when the headlights are on, yes there's a little bulb in it. Take the center bezel off (just pull, it snaps in), and underneath it you'll find that the switch bezel is screwed in as an assembly. You can unscrew it and pull it out, and you should be able to find the bad bulb.
If you are hoping it will sport an indicator light when you are using the wipers, as the defrost switch lights up with use, no dice. There's no "on" light in that switch.