after moving the dip switches, you have to power down then back up for the change to be recognized. the two m-7 sensors dont directly control the pump, they control whether the heater comes on, and stays on, or not. Check the voltage rating of your circ pump, and if one of the other pumps in the machine has the same rating, plug one of them into the circ receptacle on the board, this will verify if power is going out to the pump. If this runs ok, then the circ has a problem, they are tough to work on but it may be as simple as a capacitor change, or cleaning the stator and winding tunnel. SN codes are for the sensors on the heater tube.