Dash lights blink with turn signal

So, the alternator in my 2000 Mitz Galant just went out and my dad and I changed it, now when I drive my car sometimes the brake and battery lights come on while I’m driving and come on and blink with my turn signals (both of them). It is an intermittent problem, and I took it to Advanced and they said everything looked fine. Can anyone tell me what’s wrong with my car?

The warning lights coming on indicates a problem with the alternator. It appears the problem is intermittent. Hopefully you can exchange it for another one.