A seat includes a seat frame and a resilient web supported by the seat frame. The web is adapted for movement between an at rest condition in which no operator is seated on the seat, and a deflected condition in which the web is deflected with respect to the frame in response to an operator seated on the seat. A switch actuator is mounted to the web and is movable between a non-actuating position when the web is in the at rest condition and an actuating position when the web is in the deflected condition. A switch is mounted to the frame, the switch includes first and second parts movable with respect to each other to open and close an electrical circuit in response to the switch actuator moving between the non-actuating and actuating positions.