I have a 2.5NA 1987 and just fitted a new alternator. The problem: Battery warning light won't go out. Batter is ok, hokding 12.2 to 12.5v. Alternator generates 14.5v. It's branded (Hela). Checked and cleaned all connections. Diode is ok (0.509). Voltage at the sensor post is 12.2v on ignition...