anyone know where oil pressure light sender is located?

OK, I've worked on a bunch of cars and motorcycles, but never have i found the engine compartment area so haphazard and disorganized as my supercharged Xterra.

I'm trying to add a sender for an oil pressure gauge. Anyone know where the idiot oil light sender is located on the engine???

Thanks.

Right on the back of the oil filter mount.

Brent