OK, had someone read the DS while i was driving. The voltage starts to dip as soon as i hit the gas, but it didnt go below 12.9. Is that low enough to cause the light to go on. At stop lights it sits at 13v til i start accellerating, then it goes to 14v. So, the alt is a new 200amp unit, and the battery is about 5 years old. My guess would be have the battery tested.