I just recently bought my car, I have never had this issue before! I have a 99 v6. When driving at a steady rpm the battery light will come on, sometimes just flash, it's all random! I had the alt and battery tested last night, both were good! The guy said it looked to him as if someone had put a system in it at some point and had to have an alt with higher watt output to carry it all and seems now that it is over charging! My gauge does show the battery to be just above the half way mark! Need anyone input on what this may be! Husband drives over the road so be is't here much to help me!