DeVille V8-4.9L VIN B (1995)
Oil Pressure Switch (For Fuel Pump): Description and Operation
Oil Pressure Sensor
As a backup system to the Powertrain Control Module (PCM) and fuel pump relay, the fuel pump can also be turned "ON" by the fuel pump switch and
engine oil pressure sensor. If the PCM or fuel pump relay is faulty and the engine is cranked, the fuel pump switch and engine oil pressure sensor
contacts will close once oil pressure is built up and will provide battery voltage to the fuel pump.
A faulty fuel pump relay may cause long cranking times and should set a Diagnostic Trouble Code.
