Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect plug X22 from the PCB
Measurement:
Test 1:
Measure the resistance between pin 3 (blue) and pin 5 (red).
Resistance should be approximately 13.8 kOhms.
Test 2:
Measure the resistance between pin 4 (white) and pin 5 (red).
Resistance should be approximately 10.3 kOhms.
Measure the resistance between pin 3 (blue) and pin 5 (red).
Resistance should be approximately 13.8 kOhms.
Test 2:
Measure the resistance between pin 4 (white) and pin 5 (red).
Resistance should be approximately 10.3 kOhms.
Isolate as per TOPs P4
and refit as necessary