I am trying to wire my tachometer to my rover v8. I have done it all as per the diagram except the positive to the ignition switch. My car has two switches, one small toggle switch for the coil and large button for the starter. I have a + battery terminal post on the firewall which has a safety cut-off switch between it and the battery. Does the positivetach wire go to the toggle switch so it is only live when the ignition is on, or to the battery terminal post? I only turn on the safety cut off switch when I starter anyway, so it would not drain the battery overnight or anything.