I have a 2010 mazda b4000 with 4 litre battery light came on so tested battery was charging at 15.6 volts. Replaced alternator then battery light wouldn't come with key on and would come on when running putting out 13.5v. Replaced alternator again now battery light comes on with key on but still does shut off but I am reading 14.4 at the battery. I have ordered a haynes manual any suggestions would be appreciated thanks.