A problem that EVs have from time to time is when the driver forgets to unplug the car in the morning before leaving. This leaves an embarrassing tail trailing behind the car. The common fix to this is to add some kind of interlock so that the car wont 'start' with the cord attached. Originally this car had a relay hooked up so that if there was AC power present at the charger inputs a pair of wires would open circuit which would then disable the 'start' function. The problem with this method is what happens when the cord is in, but not plugged into the wall? You still have a tail!
My solution was to put a switch (this one is really overkill, but it was free) that opens when the door is open. Now if there is anything in the charge hole, the door can't close, and the switch remains open. The control circuit I'm designing will use this signal to turn on a dashboard indicator and prevent the car from going into start mode.