Oil pressure switch wiring - ScannerDanner Forum Jan 19, 2018The Oil Pressure Sensor, remember a pressure sensor varies a voltage signal based on a fluid or gas pressure. A switch is ON or OFF like a oil level switch. The Oil pressure sensor is located on the top of the motor, drivers side at the rear. The voltage signal is sent to the pcm and then to the cluster to the oil pressure gauge. GM Oil Pressure Connector Pigtail - WiringProducts, Ltd. 3-Wire GM Oil Pressure Sensor Connector. 1987 and Newer. Fits All GM 3 Pin Switches. Works for Various GM Gas and Diesel Engines. Replaces GM #12085499 and AC-Delco PT121.