My mechanic recently replaced my alternator with a rebuilt ( a couple of months ago ) and two or three weeks ago He also changed out the 5 year old battery ( interstate)
The replace battery words in white and red battery go on for about about 5 minutes then off -repeatedly.
My mechanic tested the alternator and the Battery and says Both are fine -
I rely on the car to make long trips -for my business - any idea whats going on ?

update- now both are on continuesly


If i had to guess id say alternator- ?
Thanks in advance !, Tony