Danno

The idea of most lighted switches is to locate them in a dark or poorly lit room. They are very typically very low current devices such as a neon bulb or an LED. They operate by getting their neutral return through the device being switched--this often assumes it's an incandescent bulb. When you turn the switch to on, it shorts out this light inside the switch and operates the attached device (the light fixture, maybe an outlet with a lamp, etc.)