pls help. abs light on, brake light circuit failure too, alternator bad?

[JE BMW]

so i was readin a bit, came to the conclusion that i might need a brake light switch. that d probably take care of the brake light circuit failure.
now i noticed some knocking, my fnd said it was coming from the alternator, he checked with a stethoscope. he said it was a bad bearing. the knock sunds faster when idle.
if it is the aternator, could that be the cause that the abs is on i think i read something about not givin enough voltage. but i cant find the post anymore.

do u guys think that if i change the alternator, the abs light will come off or do i need to fic something else.

thanks in advance for your time.

bump