A switch actuation detection unit has a switch actuation voltage reception terminal and a logic circuit. The logic circuit includes a first port, a second port, a zener diode, and a signal port. The switch actuation voltage reception terminal receives a switch actuation voltage. The first port is connected to the switch actuation voltage reception terminal. A first terminal of the zener diode is connected to the switch actuation voltage reception terminal while a second terminal of the zener diode is connected to the second port. The signal port provides a plurality of pre-determined switch state signals.