In a preferred embodiment, the invention provides a fiber optic pressure sensor apparatus which includes a light source, a reflective sensor diaphragm movable in accordance with pressure in a medium and an optical fiber coupled to the light source for delivering a first wavefront of light to the reflective sensor diaphragm. The microcontroller doing the plate position control commands full closing voltage from throttle motor drive electronics. The sensor assemblies are responsive to a condition of the lower seat cushion.