The oil pressure sending unit is the mechanism that regulates a vehicle's oil pressure light or gauge, depending on the vehicle. The sending unit applies oil pressure to either shut off the oil pressure light or activate the oil pressure gauge.
The location of the oil pressure sending unit depends on the type of engine the vehicle has. The unit is usually located on the output side of the oil pump on older vehicles. Newer models tend to use a screw-in type in which a transducer is attached to an electromechanical switch. The cost of an oil pressure sending unit varies depending on the vehicle. As of April 2015, prices range between about $30 to over $100.