(if you've put your meter across the battery to do a current test A) 6 amps is like way way down B) im surprised your meter still works and C) and im even more surprised your dont have burn marks on your hands)
It isn't across the battery, disconnect earth lead from battery and place meter on earth lead the other end on battery- put meter onto amps dc and i think you'll find my hands and meter are still fine no scorch marks or anything. The meter reads 6.9 amps if you were to put a test bulb in between also it should light up if you have a short. Mines doesn't light up.
I'm beginning to think battery or alternator but i'll need to try the alternator connected itself.