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why cant you just put the alternator wire on the side of the main kill switch going to the front of the car so that the alternator is killed when the switch is off?



If you put it on the side of the switch going to the front of the car, it won't cut off the power supply from the alternator. As long as the alternator is turning, energy is being supplied. The car will continue to run, just like when you have it running and pull the + battery terminal from a car, due to the charging system.

It has to be on the battery side of the switch.