alternator please help

My aurora was having a problem with really low voltage. The volt gauge was comming on along with DIC tellin me to check the charging system now that i found out the alternator was not charging the battery. I just replaced it. after i started it up every thing was all good. But then i noticed that my lights were flickering, and after about a minute the volt gauge came back on. but my volts are at 14.9 running. clearly the alternator is charging the battery. but why the flickering light and the volt gauge is still on. Is there trouble codes that have to be cleared.

Please help i am getting real frustrated with this car.

thankyou Mike.

take it back to the place where you got the work done. Tell them, (because you have a warranty)that this problem is still going on. Now, remember that a car has many functions. So it may not be their fault, so have them check the charging system. Its an hours time. Just wait and see if they tell you its what they did the first time, thats the problem. Another words they may see your putting out too much voltage. They will check the charging system
and let you know whats up. Its great that you have found a shop that does this kind of work. Note: see if they have a drivability dept. (for the check engine light)