Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Lower the PCB
Remove the 4 way connector from the left side of the PCB
(as highlighted opposite)

Measurement:

Test 1:
Turn the ON/OFF switch OFF.
Measure the resistance between the red and brown wires.
Expected resistance open circuit.
Test 2:
Turn the ON/OFF switch ON.
Measure the resistance between the red and brown wires.
Expected resistance short circuit.