should be on the driver side up from where the the oil pan meets the block. You'll need a allen wrench to get it out. If that fails buy a Haynes garage manual it will tell you how to do this and more, they cost like $15.00.
1997 grand cherokee 4.0L, forest green, 3" skyjacker, 1" spacers, adj. front track bar, skyjacker sway bar dissconnects, procomp steering stabilizer, 31" super swamper LTB's, safari bar w/ 2 KC's, custom roof rack w/ 2 KC's, tow hooks front and back, CB, dynomax turbo muffler, custom K&N filter charger, 2 12" sony explode subs.