My truck keeps draining the batteries. The odometer reading will stay lit up constantly. I disconnect the negative terminals on my batteries and volt meter between neg cable and battery reads 12.78 volts.A lot of draw!! All fuses except cigarette lighter and back up light will light up test light.i unplugged the wire plug on alternator incase it was shorting out but same reading at battery! I'm told to remove and clean all ground wires incase they r corroded!! I'm getting stumped can someone please help me in further investigation of this issue ???

 

Welcome to DF! Moving this to the 3rd gen Ram section.