I have changed the alternator and battery. Cleaned several wires. My dash board reads -13. If I leave the battery connected when running it drains the battery very quickly. I have had the battery and the alternator re tested. They are supposed to be good. When I put a volt meter on the alternator, I get 14.2 volts. When I test at the fuse box I get the same. When I test at the battery I get the same. Can anyone tell me what this might be. It clearly looks like the dashboard panel is correct in -13