(These generalizations, depend significantly on year, make, and model.) Generally speaking, in the “OFF” position, the ignition switch doesn’t connect anything in the “ACC” position, the radio or fan may be energized in the “RUN” position, the engine control module is energized and finally, in the “START” position, the starter relay is engaged. Inside the ignition switch, several contacts connect vital electrical systems needed to start and run the car. The ignition switch itself is connected to the ignition cylinder by a shaft or lever.
With all the covers removed, it's easy to see how the ignition cylinder relates to the ignition switch and steering wheel lock.
