Back in the dinosaur days when i owned a 71 Hemi GTX, and a 71 Cuda, those cars still came with a cigarette lighter.
I never smoked, so i never needed to use those lighters.
I wanted to install a hidden kill switch, as a theft deterrent.
I remove the "guts" from the back side lighter, and installed a round, cylindrical, type of button switch in the housing.
Then all that i had to do was use the push on, push off, knob, to activate the switch, to kill the coil.
Always worked well, and it was a hidden kill switch, that you wouldn't know anything about.