Cannot locate the location of the temperature sending unit on a 96 ford f150 4.9 L engine

 

The one for the gauge should be on the passenger side towards the back (on the side of the block) hidden behind the manifolds.

 

Chris is correct look just above the starter. It’s small and mine was completely covered in gunk but it is in fact passenger side of block down low near the starter. Look above starter for any wires going into a bung.