I have a 78 280. About a month ago I started having problems with the lights dimming and now the car will only runs for a couple of minutes before it drops to below 6volts (lights off). I had the alternator tested: 16volts. The battery is 2months old, and I can't think of what could be wrong. The fusable links are all good. I figure I have a good short somewhere, but I don't know of the first place to start to identify it.