Battery light still flashes after replacing the wiring harness to the alternator on 2000 Mercury Cougar

I bought the car 7 months ago and replaced the alternator a week later. it worked fine for awhile but I noticed the dash lights going dim and then getting brighter. Battery light just started to come back on so I took it to a Ford dealer and they replaced the wiring harness to the alternator. that fixed it for about a week, now the battery light is flashing when I drive down the Road.

Asked by for the 2000 Mercury Cougar
I did they act like they don't want to mess with it has been there for 3 days. Could the alternator have went bad since I replaced it way before I had wiring harness replaced?
yes that is poss call the service manager and tell him whats going on and see if that will help
Ok thanks. I will do that I will post when I know something.