So my truck wont crank or start unless its jumped started, it has brand new batteries, starter and alternator. It started like a new truck for the last week then all of a sudden volt gauge shows 8v and got nothing at all, so i got it jumped started and it fired right up but as soon as i removed the jumper cable the gauge went back to 8 volts. I drove home and when i tried it again the gauge was fluctuating between 8 and 12 volts and everything was flashing on then off again as the gauge was fluctuating. I tried a jumper cable from battery to battery, from battery to starter, from battery to alternator and finally from battery to starter solenoid on the right side fender and nothing was changing. Can anyone help me ? Thanks !