Oil Pressure Gauge
Turn ignition switch on (DO NOT start engine). Wait 1-2 minutes and unplug sender wire. Separate oil pressure sending unit connector from unit. Insert 120 ohm (104 ohm for Ram-50) resister between gauge and ground. See Fig 1 . Bulb should light or gauge should read about 60 psi (4.2 kg/cm2 ). If gauge does not have psi marks, needle should point at second of 2 center marks.