Not sure about the control card, but you should check the telephone cable running between all the units, as this is the communications network for the system. Many have found the cord ends sitting in water (probably from condensation) or just poor workmanship at the connectors. This may solve your problems. For mine, I have to pull the center AC from the roof to get to the cables, but the others I can access through the ceiling plenums.
TV: 2015 F-350 DRW, CC, 4x4, with 14k GVWR package, 98 gallon TransferFlow Aux Tank, Timbren Shocks
TH: 2014 Voltage 3950, Sailun S637 all around