[HawgRyder]

Just think of the circuit you want to protect as a piece of wire.
The wire goes from the fuse panel to the pump/starter/or ignition unit.....you are going to break the line in a convenient place...and join two wires to the broken ends....and take those 2 to a switch.
When the switch is on...it's just as if the wire was never broken....when its off....the power will be interupted .
The great thing about this is....the thieves will not know about your particular system.....they have no way of knowing what you have done...unlike a commercial system....where they can buy one just to find out how to defeat it.
Bob