I believe they have the answer you need. You not only have to cut the power to the switch ( by turning the shut off switch) you have to cut off the power from the alternator because with the ignition switch still on the alternator is still in on mode with the exciter wire hooked up or as a one wire. Running the "batt" wire from the alternator to the battery side of the cut off switch should stop the feedback to the system. That is a few bucks worth of 8 gauge wire and two terminals. That way it would not supply power to the electrical system when the switch is thrown but everything works when the switch is in the on position. I was thinking relay in the exciter wire with the power wire connected to the battery cable but feedback from the alternator might keep the relay triggered and not be effective. As mentioned previously if you have an electric fan you may also have to eliminate feedback from it. Some turn into a generator when the key is turned off and they are still spinning.