Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove connector M2 from the PCB
Remove the 2 wires from the low pressure switch
Remove the 2 wires from the low pressure switch
Measurement:
Measure the resistance of the wires running to the pump proving switch from pins 3 and 4 on connector M2.
Expect continuity/zero resistance on each test.
Also visually inspect the condition of each of the wires.
Are the resistances measured as expected and is the harness in good condition?
Expect continuity/zero resistance on each test.
Also visually inspect the condition of each of the wires.
Are the resistances measured as expected and is the harness in good condition?
Isolate as per TOPs P4
and refit as necessary