I just bought a new (to me) tow vehicle. Its a 2000 Silverado with the 4.8L and 55K miles. Everything checked out fine, but now my red battery is lighting up intermittently on the dashboard message center. It is supposed to indicate a charging system problem. I tested the battery and the alternator and they look ok. The volt gauge on the dash reads 14v and doesn't move when the light comes on. If I shut the engine off and restart the light will go out. Any ideas? Thanks in advance