You need to remove the dog house (rear engine cover). The oil pressure sending unit is located next to the distribiture. It usually has a plug with just one wire.
Mounted right above the oil filter,
The 1985 Toyota Camry oil pressure sender is located on the left-hand side of the engine. The oil pressure sender will be just above of the oil pan.
The 1989 Buick Century oil sender is located inside of the oil pan. You will need to remove the oil pan in order to view the oil sender.
The question should read 1989 Ford F250 7.4 liter engine...Location of Oil Pressure sending unit...
check the sender
the oil pressure sender on a 2000 gmc is in the back of the eng. top side
Next to the oil filter
Round shape oil pressure sender on the passanger side to the right of the oil filter. Oil pressure sender sends how much psi your oil pump pushes out to the ecu.
Assuming the engine is not knocking, indicating a serious mechanical problem, its most likely the oil pressure sender.
The oil pressure sender on a Mazda B2500 2.5 is located on the bottom of the engine near the oil pan. It constantly monitors the output and circulation of the oil pump.
The oil pressure switch and oil sender for older 454's are mounted on the lower left front of the engine block just above the oil pan.
Oil pressure sender /fuel pump switch for 1995 Pontiac transport 3.1 is located between oil filter and starter at front of engine.