Concord L6-258 4.2L VIN C 2-bbl (1982)
Oil Pressure Gauge: Testing and Inspection
This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are connected in
series. The sending unit consists of a diaphragm, contact and a variable resistor. As oil pressure increases or decreases, the diaphragm actuated the
contact on the variable resistor, in turn controlling current flow to the gauge. When oil pressure is low, the resistance of the variable resistor is high,
restricting current flow to the gauge, in turn indicating low oil pressure. As oil pressure increases, the resistance of the variable resistor is lowered,
permitting an increased current flow to the gauge, resulting in an increased gauge reading.
TROUBLESHOOTING
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.
