The oil pressure sending unit is located just above the oil filter at the rear center of the engine. You will need to lift the front end in the air to crawl underneath. Remove oil filter to access the sending unit just above it. Unplug electrical connector, and use wrench to loosen and remove the sending unit from engine block:
Depending on brand, $10.
Duralast / Oil Pressure Switch Part Number:PS100 Price: $8.99