[blykins]

You don't need a ground to it...All you need is to know what accessories you want on what position. Of course your main hot wire will go to one post....your accessories that you want on when the key is in the "on" position, and your starter will go on the other post. To find out which is which, orient your switch so that you know which side the off position is...then just put a lead from a continuity tester on that post....turn the key to the "on" position, then touch your other lead to the other posts to see which one it is....it's really simple. The accessories that will be turned on by this switch will have their own ground...you don't need a ground to the switch itself. Its only purpose it to supply juice to wherever you want it.