Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Gain access to PCB (use insulation mat as necessary)
Disconnect connector M5 from the PCB
Gain access to PCB (use insulation mat as necessary)
Disconnect connector M5 from the PCB
Measurement:
While manually making the pump proving microswitch (temporarily taping it may make this test easier) measure the resistance between the two white wires of connector M5.
Note:
If microswitch has been taped remember to
remove tape once test is complete.
Note:
If microswitch has been taped remember to
remove tape once test is complete.
Isolate as per TOPs P4
and refit as necessary