12V DC Switch Connection?
24 V switching may damage the switch contacts if you are switching high current and particularly if the load is highly inductive.
24 V will probably pass too much current through the LED so you would require an external series resistor on the LED terminal.



simulate this circuit &ndash; Schematic created using CircuitLab
The safest option is to measure the current drawn on a 12 V supply and add a series resistor to drop 12 V at that current.
Hellas Digital says

Since there's an LED inside, but only 3 pin, they're a little different to wire than most toggle switches.

The anode (positive side) of the LED is connected through a resistor to the pin with a 'headlamp' (=D) symbol on it
The cathode (negative side) of the LED is connected to the pin with the ground symbol, which is the pin that is sticking out the side of the switch.
The switch connects and disconnects the (+) pin and the 'headlamp' pin

That means you have a few options for wiring:

If you want to use the switch to turn on/off something, you can use the toggle to connect and disconnect the two pins on the bottom
If you want the LED to always be on, provide 3-12V between the ground and headlamp pin
If you want the LED to be on only when the switch is connected, provide 3-12V on the (+) pin and connect ground to the ground pin.

The protective cover will automatically turn the switch off when flipped closed, but you can simply remove it if it isn't desired.