kill switch

"My engineer friend" who died................when younger designed up a circuit that read (decoded) brake pedal switch action.

He was a radio amateur and commercial maritime radio op (worked for Scripps Institute) and so when you got into the truck you sent something on the brake pedal in Morse.

I don't remember, anymore, might have been the letters CW...... Dah di dah dit...........di dah dah

Or maybe it was just "X" but that would then unlock several circuits in the truck.........the fuel pump relay, the ignition, etc. If you did NOT send the unlock, jumpering the starter would blow a fuse and render it inoperative. This was a (then new) '70 Chev K200 so it was easy to hot wire. I also "taught him" to run a chain through the hood hardware---difficult on Mopars-- and lock the hood with a padlock.