I'm a little confused on what "digital display" you are referring to? If you are looking at a digital display for your house batteries and the house batteries charge when you start the engine then the BIRD and Trombetta are working correctly. If the digital display shows the house batteries discharging when you turn your lights or fog lights on, I would guess that you have a short somewhere in your system. The BIRD is designed to separate the coach and house batteries if the coach battery is discharging when the alternator is running. That is so that if you have a short in the house batteries they will not discharge your coach batteries.
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