Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove the cover from the water pressure switch by pulling backwards along the wiring
Measurement:
Remove and inspect the water pressure switch wiring harness for signs of damage and test resistance across the brown and white wires.
Expect a resistance of approximately 740 ohms.
Expect a resistance of approximately 740 ohms.
Isolate as per TOPs P4
and refit as necessary