Making a car difficult to steal

67Dart273 said
Of course they can power the starter. They are known as "jumper cables." Every good (pro) thief has a pair. How long did that take?

But the only place they could jump it from on the car would be the alternator post since the battery is locked in the trunk, and the only thing they would power is a fire because there is no way they will pull enough juice on that circuit to turn the starter over.

67Dart273 said
What is the circuit titled "security interlock" and how is it powered?"

That is laid out in the top right corner of the diagram.

It is a hidden switch that doesn't allow power to the starter circuit if the switch isn't engaged. It wouldn't be any different than a standard kill switch in the starter circuit other than this circuit powers the solenoid in the trunk instead of the relay that would normally be under the hood.

67Dart273 said
The thing is, if you can keep them from jumpering power to ignition, fuel pump, etc, it won't run. The only thing they can do is tow it or haul it, whether the starter cranks or not. What if it's a stick car? They can push start it So you need to get power OUT of the hood area.

That is exactly what I am trying to do, get the power out from under the hood, but don't see any way to cut the power at the alternator stud without some kind of a constant duty solenoid. This at least gets the battery and starter power out of the engine compartment and would hopefully leave someone a little baffled for a bit. The car is a stick and they could push start it, but I suspect that would make it less likely they would keep at it. I don't see them bringing a battery with them, but it is always an option. They pull another car along side, but that isn't very sneaky.