When shopping for switches, it’s really satisfying to dig through a drawer full of awesome options for your project, but it’s easy to get stuck with something that’s not quite right if you don’t read the package carefully. I identify with Randy Sarafan’s illuminated switch problem:
I was about to wire it all up into my newest guitar pedal when I realized that this switch actually required 120 VAC to illuminate! What’s up with that? This bugged me a great deal as I would be working with low-voltage DC, not high-voltage AC. This was not going to do.
I immediately resolved to replace the little bulb inside with an LED. This required a near total dissection of switch, but after a little figuring out, I am happy to report that the mission has been accomplished. Follows is a method for converting an illuminated Radioshack switch from 120VAC to 3-12 VDC.