I got to thinking about what happens after I start sinking some more money into the van. I'm going to have to consider anti-thief devices. One problem with alarms you buy is that the thieves already know how those work. Here's an idea I came up with.
Mount four toggle switches on the dash somewhere. Not hidden. Cover the four switches with safety covers like this:
These serve two purposes. One is to prevent flipping the switch by accident but it also hides the position of the switch from the casual observer. Wire one switch to the coil hot wire. Wire another switch to the inertia switch.
Here's where it gets interesting. Each of the two other switches, when flipped, would force a short and blow a fuse when the van is started. I've not figured this part out 100% yet but I'm close. Need to know of two fuses that would prevent the van from starting (or just wire both switches to blow the same fuse). Also have to come up with a way to safely cause the short without damaging anything but the fuse.
If you used four two position switches then there would be 2x2x2x2 = 16 possible combinations and only one would work. Put the switches in the wrong position and now you have a blown fuse to worry about but as a thief you won't know that. How long will a thief spend trouble shooting a vehicle that won't start before he just gives up. If you use three position switches that would increase combinations to 3x3x3x3 = 81. Even better odds.
Before you get out of the van set the coil and inertia switches. If a thief breaks in and tries to start the van it won't start. So he sees the switches and starts flipping switches. Odds are he'll most likely blow a fuse before he can get the right combination. Once the fuse is blown no combination of switches will allow the van to start. If you hop back into the van and forget to reset the coil and inertia switches the van just doesn't start. No blown fuse. Just put the coil and inertia switches in the proper position and off you go.
I know this won't work against a flat bed truck hauling away the van but I don't think that is how most vehicles are stolen.
What do you think?