Those rocker or toggle switches with 3 wiring tabs are for automotive use. The two tabs that are close together are for the switch's internal bulb, with the tab nearest the edge being the positive voltage input and the other tab going to the power supply ground. The tab near the other edge goes to the device you're wanting to turn on and off.
The bulb in the switch obviously needs to have a negative input as well to illuminate - the bulb won't light on a positive input only !
One lead will be your positive input that is being switched for your accessories - one terminal will be the output for that same positive input OUT to your accessories, and the last terminal will be the ground (or negative) required for the internal bulb to illuminate.
One thing you may want to consider .... these type of illuminated switches usually contain an automotive type bulb and as such will draw a fair bit of current from your power source that could be better put to use than lighting a switch ! You may want to use a standard switch and wire in an LED as a power indicator.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Generally there is a wiring diagram on either included inside the package or on the side of the box.
Is this a switch that is lighted when the circuit is closed, or lighted when the circuit is open?
I would think that a normal spst switch would have only two blades, and when the circuit is closed the switch light (or LED) would be in parallel with the circuit and light when the circuit is closed. The fact that you have three blades sounds to me that in one direction the switch closes the circuit and the light would be off, and when thrown in the other direction the circuit is open but there would be a circuit through the switch light to turn the light on.
Just my guess.
I plan to use a 12VDC wall wart to power lights in a series of buildings and I plan to put in a 12 VDC SPST lighted rocker switch to turn them on and off but I don't know how to wire the switch (I've always used Atlas Connectors to turn lights on and off). The switch has three blades. This is a pretty basic question but I found myself totally confused when I started to hook up the switch. Can anyone give me a simple explaination and/or wiring diagram?