A while back I was driving my jeep and the radio quit playing and the lights began to dim and the car slowly died like the alternator went out. I had the car towed home, tested the battery and it showed to be bad. I bought a new battery , installed it and still nothing. I took the alernator and had it tested and it came back ok. I replaced the battery cables too. I do not get anything. The accesories do not even work(interior lights, radio, etc). The headlights will come on, but that is it. Any ideas?