How fix 2002 grand marquis trunk it pops open when switch in gear

Just experienced the same problem. Found a wire had pulled out of the wiring harness connector that goes to the trunk release. The harness is located near the left hinge. The wires going to the harness go around the hinge. The connectors are difficult to seperate because you can't see the release. I wanted to unplug the connectors to see if the car could be driven without the trunk opening. The fix was to find the corresponding wire to the one that had pulled out, stripped the ends added a length of wire to allow me to connect the ends with wire nuts, black tape the wire nuts then join the connectors. Essentially I added am jumper to bypass the harness connectors. Works great. Someday I may look into a permanent fix but am confident this will last.

Check and make sure it's locking down,and isn't out of adjustment at the latch. don-ohio