In older cars the position of the switch directly controlled the electrical connection. Having the fan speed at position 3 directly controlled how much electricity went to the fan and thus, how fast they spun.
In modern cars, most switches are simply instructions to the onboard computer about what you would like it to do. So, turning the fan speed knob simply tells the computer to make the fans spin faster. The computer handles the particulars about voltage and current.
But, now that you have software control, that means that you can have multiple inputs that all control the same function. You can turn the fan speed knob or you can go into the onscreen controls and set the fan speed. So, now that the knob position is no longer in direct control you want a design where the setting and the position don’t get out of sync. So, you end up with switches that reset to neutral after you’re done interacting with them.
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