Battery went bad - that happens, and all battery terminals corrode, but this multi-connection copper connection has been corroding to the point that it will not tighten onto the new battery terminal. The copper plate that has four or five connections to it has corroded to the point that I had to jerry-rig a shim out of hammered out lead fishing weights to fill it in so I could get a good connection. Dealer said it would require a replacement of the full harness at a cost of around $250. Bump that! I am looking for a replacement copper plate to reconnect all the terminations, and do it myself.