[ThePair]

There's an inline fuse for the hot line coming from the battery to the jack -- it should be checked to make sure it's not blown. Also, the ground/return from the jack to the battery isn't a wire, it's through the frame. Do you, by any chance, have the swing hitch? If so, you may not have a good enough connection back to the battery/ground to allow the jack to function. Some have attached a ground wire to cross the "gap", others have tried sanding away any paint for a better connection at the hinge pin for the swing. I, personally, have not had a connection issue, but I know others have posted this in the past.