Where does the fuel pump wiring harness ground itself on a 1997 jeep grand cherokee?

Wise poster, rare here.
if the voltage across the DC pump wires
are not 12v (inspec)
the move the meter to ground and Plus DC wire. if 12vdc good
if you move the meter to ground on pump MINUS
and the black lead of meter to chassis
and it read, 12v 8v wrong, or not 0.5vdc good, the ground is bad.
never a reason to guess, with meter in hand use it correctly
there are 3 tests there not just 1.
best tests is cranking,
also the voltage is key here, some pumps run and pull 3 times
normal current (we use an ammeter too, test 4 , sure)
and will cause voltages to drop at the pump.
say battery is 12v but at pump its 8v, and ground is good
then pump is drawing excessive current.
some can be 1amp below fuse rating and no fuse blown.
with my lab scope i can even see a shorted DC motor commutator
before any loss of fuel pressure.... facts. all.

I looked at the wiring diagram and it appears the pump is grounded to the undercarriage, the exact location is not shown in the diagram I have, but just do this, use a ohmmeter (DVOM) and measure the ground for the pump resistance, it should be less than 5 ohms (pump connector to a good clean piece of sheetmetal ), that would indicate a good ground or better yet just drill a hole and run a new ground if needed if the ohm check is out of specs. You did check the fuel pump shut down relay before buying the pump? Here is a link to the diagram. http://ww2.justanswer.com/uploads/NV/nvltgo/2012-12-28_225705_fuel2.jpg

With fuel pump module connector loose, use a test lite connected to battery voltage, touch the black wire terminal, if the lite comes on, the ground is good enough to turn on the test lite. I wasn't sure of engine liter size, but, ground is usually black. As far as physical location of G300, I don't know? I have had good luck with redundant grounds.