[Michael C Henry]

What got grounded .The switch shouldn't have any electrical contact from an inside contact with the outside of the switch when the switch is operated it makes connections internally with the terminals.Unless the contacts were no longer in there proper positions which means the switch is no good anyway.
. Check the switch by dissconnecting all wires, remove the switch from the dash .Use a multi meter on the ohms position .connect one probe to the" Bat" terminal,the other to the metal outside of the switch there shouldn't be a connection.Then operate the switch and see what terminals get connected in which positions of the key.(Off )no connections ( ignition position) ignition and accseesory terminals should be hot .(Start) is the spring loaded podition start should light up while being turned, Ign should stiil be hot. In (accessory position) battery and accesory should be connected.If you have a connection to the switch housing ,the switch is junk. If connections aren't where and when they are supposed to be its junk. Switches are realitave cheap. A Circuit breaher between battery and switch could be saver.Butt If it fried internally ,what did you have connected to draw that much current?