The switch is screwed into an oil filter adapter located at the oil filter. You will recognize it by the wiring on it.
On the 4.0 liter OHV - V6 engine it is on the drivers side of the engine below the power steering pump
Chrysler didn't have a 5.7L engine in 1999.
Oil Pressure Sender and SwitchFord Ranger/Explorer/Mountaineer 1991-1999 Check Related Links below.
The engine oil dipstick is on the drivers side of the 4.0 liter V6 engine in your 1999 Ford Ranger Helpfull
According to Gates ( they manufacture timing belts etc ) the 2.5 liter engine used in a 1999 Ford Ranger is NOT an interference engine
drivers side of engine , below the power steering pump
( 160 horsepower ) for the 4.0 liter OHV , V6 engine in a 1999 Ford Ranger
2.5 liter 4 cylinder , or the 3.0 liter or 4.0 liter V6
The sending unit for the oil pressure guage on a 4.0 L OHV engine is on the driver's side of the engine below the power steering pump - Helpfull
I believe the sending unit for the oil pressure gauge on a 4.0 L OHV engine is located on the drivers side of the engine below the power steering pump
( 5W-30 ) for the 2.5 liter 4 cylinder , 3.0 and 4.0 liter V6 engines ( according to the 1999 Ford Ranger Owner Guide )
4.0 liter OHV - V6 , 3.0 liter - V6 , 2.3 liter - 4 cylinder