I had problems with my alternator light on my dash flashing at me for while. I wrote it off as a faulty light because it would flash when I hit bumps. I was in the parts store parking lot when the battery gave up the ghost. So I replaced the battery and alternator (using the v-belt pulley from the original alternator because the new one, which was a remanufactured one, came with a serpentine pulley). I continued to see it flash at me going down rough roads. Come to find out, my voltage regulator connection was loose. I replaced it with a new voltage regulator and didn't see any problems. It has started flashing again, but this time only when I am going faster than 55 mph. Could this be the pulley slipping? If not, what could it be?