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The Ultimate Kill Switch ?

Mach1 Driver

Active Member
On Page 1 of the PDFs below, it shows three methods to disable the ignition. Page 2 shows three ways to disable the fuel, and page three shows how to use a magnet and reed switch to turn those systems off. The advantage of a magnetic reed switch is that it can be hidden behind any plastic part and no one will know where it is or how to turn it off. With a normal kill switch you run the risk that the thief will find the switch. This won't outsmart a determined thief, particularly one with a tow truck, but it will stop most.
These are the magnets on my key chain. These little guys are very strong for their size and are normally used as jewelry clasps. They come in pairs with a small through hole down the axis and a larger hole that goes partway down on the other end. I used 30 lb mono-filament, tied a knot and pulled it into the oversize hole. Pull on the loop and you can separate and hold one of the magnets. If you don’t want to hang the magnets off your key chain you could just let the magnet grab on to a chunk of steel somewhere in the car and it won’t go anywhere. I prefer to remove the magnet from the vehicle.
The reed switch sits to the right of the magnets. It is small but the electrical specs are more than adequate for the job.

This is a demonstration of how well the magnet and reed switch work. Here we have an easily removable piece of plastic trim. The reed switch is attached to the inside with a piece of Scotch tape. The ohmmeter is connected to each side. The magnet is attached to the ohmmeter with scotch tape and supported by the mono-filament line. The magnet is about 1/2” away from the reed switch and has successfully closed the switch- you can see from the ohmmeter that it is not an open circuit but has 14.6 ohms. This rather high resistance is probably due to my ratty old alligator clips, but even this is more than adequate to operate the relay shown in the PDFs, and get you on your way.


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