Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect mains voltage plug from pump then
remove red clip to expose connections
Pull X1 back slightly to expose test pins

Measurement:

Check for continuity (zero resistance) of the blue and red wires running from the disconnected plug to X1 on the PCB.
Red = X1 Pin 1
Blue = X1 Pin 2.
Inspect harness and connectors for good overall condition.