Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect connector X1 from the pump PCB

Measurement:

Test 1:
Measure the resistance between pins 5 (brown) and pin 6 (blue) of the disconnected X1 plug.
Resistance should be greater than 1M Ohm.
Test 2:
Measure the resistance between pin 5 (brown) to a suitable earth point.
Resistance should be greater than 1M Ohm.