Are you sure it actually has one? Most cars don't. Perhaps this is why you can't locate it.
You will need to run an oil pressure test with a pressure gauge.
install an oil pressure gauge
Low oil, no oil pressure, bad sending unit, wiring, bad gauge,.............
5.2 or 5.9 it is on the back of the engine, next to the distributor. 4.7 it is on the driver side front of the engine, above the oil filter. It sends a signal for the oil pressure gauge or low oil pressure warning light as equipped.
The oil gauge shows the oil's temperature. The oil pressure gauge monitors the oil pressure for your viewing pleasure.
Connect the wiring harness to the back of your oil pressure gauge. Secure the oil pressure gauge with the retaining screws.
Defective gauge, defective oil pressure sending unit, low of oil, defective oil pump.
Six-year the oil pressure gauge for your 1999 Mitsubishi eclipse with the retaining screws. Connect the oil pressure gauge wiring harness.
"T" into the existing oil pressure gauge with brass pipe fittings. This way you will have the original oil pressure gauge and the mechanical oil pressure gauge. Don't forget to use thread sealer.
5W30
No.No.No.No.
The oil pressure sensor is on the oil cooler, under the intake manifold.