The oil pressure sending unit is a variable resistance type magnetic unit that works in conjunction with the magnetic operation of the gauge system.
The sensing unit may only be tested for operation. There is no calibration, adjustment or maintenance required.
With the key in the RUN position and the engine off, unplug the wiring at the switch. The gauge should read on the LOW graduation or below.
Attach the wiring connector to the engine block (ground). The gauge should read just slightly above mid-scale.
If the oil pressure gauge tests within specification, replace the oil pressure switch.
If the gauge still tests out of calibration, replace the oil pressure gauge.
REMOVAL & INSTALLATION
The pressure switch used with the oil pressure warning light is not interchangeable with the sending unit used with the oil pressure gauge. If the incorrect part is installed the oil pressure indicating system will be inoperative and the sending unit or gauge will be damaged.
Unplug the connector at the unit and unscrew it from its mounting.
To install the unit, apply pipe sealant or Teflon® tape to the threads of the new switch and screw it in to its mount. Tighten it to 8-18 ft. lbs. (11-24 Nm).
Connect the wiring to the unit.
Run the engine and check for leaks and proper operation.