Oil pressure switches are typically used as an actuator which directly activates the oil warning light in driver dashboard when the oil pressure in the engine will fall below the preset critical level or brings a signal to the ECU (engine control unit), so to be warned about low pressure of engine oil and prevent damage to the engine. Depending on the engine construction, the oil pressure switch usually can be found in one of the most common locations: in the cylinder block of the engine or in the oil filter housing as well as at some engine types can be found in the engine head. For Detroit Diesel DD15 DD13 50 60 For Mercedes 1718/ATEGO For Mercedes Axor / Actros Adblue 600 609 4000