This is the front... not much help, except it's a pretty picture of a light,
This is the back
There are three pins. I am guessing that 2 of them are for +ve and -ve of the switch, ie. one is connected to the +ve of the battery and one is connectd to the +ve of the component requiring a switch. Because the switch has backlighting, I'm assuming the third pin is for the +ve of the backlighting wire (for when the side lights/dipped beams come on), and the earth for that is provided by the -ve of the switch, which will consequently run down through the component and to its earth. But ofcourse I'm not sure if:
a) This is correct
b) It is correct, which pin does each of the aforementioned jobbies.