I have a 66 chevelle big block car I race and street. My problem is the outside kill switch in the rear of the car, will shut off all the lights and power in the car, but will not shut off the engine. It just keeps running until I pull the alt. wire off. I have a digital 6 msd box and I know that you have to have the diod in line. The car will turn off the engine with the ignition key, but if I try to shut down everything with the kill switch the motor will keep running.Its driving me wild. I hope somebody hear can help me.

I suspect that the key switch controls the excitation for the alternator field. So, if the key is on, but the kill switch cuts out the battery then the alternator will still have power to the field. Maybe a relay inline with the field power that is controlled by the battery voltage (and the kill switch) is needed.