02 sonata charging issues

i have an 02 sonata that when we took it to a garage to get the alternator checked it test fine but yet the battery light is still on and we have to charge the battery every night and give it a jump alot. we have spent close to three months charging this brand new battery every night. we changed the big wire going into the back of the alternator and that didnt do it. but when i unplug the four wires that are together from the back of the alternator the battery light goes off and it charges itself again. im just afraid of it burning the computer or something else up so i just leave it plugged in all the time. but what should i do. where does them wires go to and what do they run. is it possible to change just the regulator in the alternator or do i have to spend a couple hundred to get a new one. please help me. im tired of charging it myself every night. it gets old after a while.