Driver's side. Take off the wheel and it's pretty much a straight shot in, 6" in front of the engine mount. It's the small white connector. You can buy oil pressure switch sockets (which I would recommend, as I changed mine with an adjustable wrench).
ok i have a question...in my 2001 sport trac in the winter if it is under freezin then my sport trac registers a check engine light and no oil pressure in the gauge. This goes till it warms up a bit and then all of a sudden the light goes out and the gauge jumps up to the right level. only when it is really cold out though. Now is this the oil pressure switch do you figure and how much do they cost?