My Oil Pressure Guage is having siezures and bounces from one end to the other. I have the Haynes book and have looked where they say the location of the sensor is, but I can't find it.

I looked all around the oil pan where it said it should be, but no luck.

Any thoughts where they are hiding it? Should I even really care? Will it cause downstream problems?
95 Grand Cherokee Limited (Orvis Edition), 5.2L
Thanks,