what's wrong with my car it has no power and it won't go into park on 1996 Lexus LS400

the lights went dim and was cutting off, when I turned the lights off it sped up then it started acting like it was going to cut off. It did cut off but will not go into park gear and it has no power

Asked by for the 1996 Lexus LS400
Sounds like possible alternator failure.