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As for the results of switching the black and red wires on the pump, I got the same results as when I switched those wires on the circuit board... the pump could either be off or on low speed, again without an inactive speed. I guess that means it's a bad relay.Another idea I had was that the topside control panel could be faulty causing no power going to the low speed pump output on the board. Not sure if that's a possibilty