Hyundai Repair: alternator voltage is too high for my car., windshield wipers, hyundai elantra

Question
1999 hyundai elantra, 2.0 4 cyl engine.  according to a code that got read and reset, my alternator voltage is too high. I dont know the code. my car has been having problems since I replaced my dead alternator with an new one. the headlights randomally go brighter than normal, when this happens the engine idles higher and if my windshield wipers are on they go faster. it also randomally does the opposite (dims, idles lower, etc..) the alternator was replaced about 6 months ago. Is the problem the entire alternator or is there a part that is linked to the alternator the cause of the voltage being too high? what do I need done to fix the problem? thanks again :)

Answer
Unlike the idle switch you asked about in the previous question, this is a serious issue.  If your alternator voltage is too high, the voltage regulator internal to the alternator is failing.  It's important that you not drive the vehicle until you get the alternator replaced; the voltage regulator is not available separately.  If the voltage becomes high enough, it could damage nearly every electronic component in your vehicle, easily exceeding the value of the car.