Did you put the KJ in water over the tires if so, then the wires inside the speakers that connect to the terminals are corroded. The wire is made of a copper mesh. Instead the copper mesh is a cloth fiber. Speakers are made with this to with stand the vibrations.
All four of my speakers went until just the tweeters where working. So after I could not stand it any more. I took the door panels off. Discounted the speakers and used and OHM meter to check continuity of the speaker wires. There was none. So I then sodered 2 wires from inside the speaker to the terminals and BINGO. speakers work.
All 4 fours are still working after 1 year. I think Jeep, made a major flaw in design of the doors to allow water to penetrate the doors and attack the electrical components.