That's an indication of a problem with the charging system. You need to have the system tested and look for a cause like a bad alternator or wiring problem.
Dec 4, 2012 at 2:50 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.