Jiggling the connector may have done the same thing as rapping the J-box itself. Next time (if there's one) just rap the box.
If handy with a soldering iron, the J-box isn't that complicated.
Remove the J-box from the bike, remove all the fuses, remove the rubber strap. On the back side you'll see five (I think it's five) heat melted rivet heads. Drill these out. Not all the way through, just drill the heads off. 1/4" drill bit is just fine, just don't drill all the way through!
Now you can remove the cover. Now remove the two phillips head screws (I think it's two) and the circuit board will pop out.
Take note of any 'dry' or cracked solder joints or traces (it does happen). Note you can use a Q-tip soaked in isopropal alcohol (do NOT use good gin or whiskey!) to clean if needed. Re-melt all the solder joints, adding a touch of fresh solder if you're so inclined.
Reassemble, don't worry about re-gluing the back on. The rubber strap will hold it. And the front is open to moisture anyway.
Report back.
Rick