Oil Pressure Gauge: Testing and Inspection

Disconnect the oil pressure gauge lead from the sending unit, connect a 12 volt test lamp between the gauge lead and the ground and turn ignition on. If test lamp flashes, the instrument voltage regulator is functioning properly and the gauge circuit is not broken. If the test lamp remains lit, the instrument voltage regulator is defective and must be replaced. If the test lamp does not light, check the instrument voltage regulator for proper ground or an open circuit. Also, check for an open in the instrument voltage regulator to oil pressure gauge wire or in the gauge itself. If test lamp flashes and gauge is not accurate, the gauge may be out of calibration, requiring replacement.