I have an immaculate 2006 Grand Caravan with 21,000 miles. Twice recently, it's momentarily lost all electrical power -- once when I turned off the key, and once when I simply opened the door to get in. There was seemingly no power whatsoever to the vehicle, then after a few minutes, all was simply back to normal. The battery and terminals are in perfect condition. Does anyone know what would cause this, and could a dealer diagnose this since it's only randomly happened twice? Thank you.