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So I'm planning on doing a fuel pump killswitch as one of my layers of protection. I already understand that this isn't a surefire way of preventing theft, but does offer some protection to novice thieves.

Basically, I've searched many threads and came up with three methods of wiring the relay for the killswitch, All of which are different. Supposedly method #1 draws power while the car is parked thus draining the battery. Method #2 uses 85 for ground rather than 86. And method #3 reverses the load and power sides (30 and 87).


So my question to all you electrical gurus is, which one do I use? or rather which one would be preferred?

Here are the following Diagrams:

#1



#2



#3

 
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You could just find a live +12VDC wire for the 85 pole and wire the switch inline there, ground the 86 pole to the chassis, and install the relay in the fuel pump wire. That'd work, too.

 
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^I was thinking about that, but for convenience, I didn't want to tap into a +12VDC. Thanks for the input though.