Problem With Car ?????

I had just put an alternator in, in my car and Im just driving along and the car just turns off. It still has current going through but I didnt have this poblem before. I dont know if it is maybe cuz the car gets hot and shuts off because I dont think the radiator fan is working properly. When you turn on the ac isnt both of the fans suppose to turn on. Also even if you dont have your ac on, if your driving all day im pretty sure that the radiator fan should turn on at least once. Help please I have a 95 gsx.

why make 2 threeds........use the same one for both questions