I am having steady brake and battery light as my engine runs what do I do? on 2002 Infiniti I35

This happened the day before yesterday and I replaced it a used Alternator of the same capacity and today it started again,

PLS ADVICE ME ON WHAT TO DO NOW

Asked by for the 2002 Infiniti I35
1 answer
steady brake light...check brakes, steady battery light...check alternator.