Pontiac Repair: problem sunfire gt baterie light, pontiac sunfire, alternator

Question
hi i I have a problem with my pontiac sunfire gt 2.4l 98.
In august i change my battery so now i have i brand new one
I also hange my alternator cuz batery light on mean my alternator is not charging the battery.so I had i brand new battery and new alternator.3 weeks after the light came back again.when he light comes on it take 1 day ans everything stop working and after cant start the car because the alternator stop working so its draining my battery.I change again my alternator.everything was fine.again 3 weeks later same problem.now it.s been " alternator .monday again it did it again.has soon as i came ut from the garage the light turn on again!!!!!now my car hes still at the garage but can t find my problem they check  ans when i have  a new alternator the right voltage is passing.realy tired of he same problem and changing alternators been the 4 time now!!hoe you can help my problem
thank you!!
Veronique

Answer
Hi there:

well it can be a few things. My first thought is if the garage is using aftermerket parts that possably the wrong alternator is being put into this car??? just beecause it looks correct doesn't mean that the internal compnents are correct. If not that the eithger ther is a wiring issue going to the alternator or the crotrol component for the laternator is bad. I belive that alternator is turned on and off the the engine control computer. Ther could be an issue with that as well. Good luck :)