I have 2004 4.7 grand cherokee that has this plug with wires on passenger side coming off the main harness and goes down behind the back of motor.
It appears that the harness has been repaired or is not original to the Jeep. Under the heat shrink there should be 4 wires with colors that can be identified on a wiring schematic. You will need to gain access to a schematic and the wires to identify what the function of that pigtail is.
While it is true that varmints can get under the hood and chew on wires, the one thing that they’re still unable to do is, unplug electrical connectors.
So, you had to unplug that electrical connector.
Show us an image of the component that you unplugged that electrical connector from.