What causes the oil pressure light to come on in a 2000 dodge neon?

Oil pressure lights indicate improper oil pressure. A pressure sensor is mounted on the engine to monitor the pressure. When the engine oil pressure drops to a level below the perameters required for proper engine operation as determined by the manufacturer, the sensor acts as a switch to complete an electrical current, illuminating the light. Low oil pressure can be caused by, among other things, insufficient oil level, or internal engine component wear, including a worn oil pump.