My new BMV 702 does not show both my house (main)battery bank and start (Aux)battery volts. The Main Voltage on the display is 0.1V while the Aux is displaying the correct 12.6 voltage. I checked the voltages at the pins(B1 & B2) on the shunt with a voltmeter and the voltages there are correct. When I swap the cable at b1 and b2. The also switch at the display with the main at 12.6v and Aux at 0.1v. Does anyone know why this is happening?