Yesterday truck runs and starts fine (battery light flickered but was fine). Today it starts fine but on the way to the gym I hear the radio starts cutting out and then the dash lights and soon everything electronic in the cab turns off. My tuner was reading lower and lower battery voltage as I drive, as low as 7 volts. Sometimes the radio would come back on if I take my foot off the pedal. WTF! How does this happen all of a sudden.