Does the bcm have to be reflashed if i get a used one

What is your question?

I have a 2006 chrysler pacifica its the touring with 3.5 auto 4wd and my gauge cluster trunk latch heater fan for front everything on steering colom ecept turn signal stopped working and few other things i do hear the alternator whine loud but it puts almost 14v wher i start van normally runs in 13v range i tried to hook code reader and wouldn't connect to read codes or any info any ideas if its bcm or ecm maybe bad ground somewhere im stumped please help and if it is bcm do they have to be flashed like ecm

What makes this problem better or worse?

Nothing constant