What it amounts to is you put a switch between coil NEG and ground. If you have a tach, you already have a wire into the interior, just tee into it and put an unobtrusive toggle to ground.
Ok I am interested in this. So if I test this, take my tach wire which is hooked up to my tach, instead attach it to ground, try to start the car and the car should not start. Correct? and there is no damage to my Coil or Dizzy by grounding out that wire, right??
