Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X3 from the PCB

Measurement:

Test 1:
Measure the resistance between pins 9 and 10 at connector X3.
 
Expect approximately 26 Ohms.
Test 2:
Measure the resistance between pins 11 and 12 at connector X3.
 
Expect approximately 68 Ohms.
Test 3:
Measure the resistance between pin 10 at
connector X3 to a suitable earth point.
 
Resistance should be greater than 1M Ohm (or O.L.)
Test 4:
Measure the resistance between pin 12 at
connector X3 to a suitable earth point.
 
Resistance should be greater than 1M Ohm (or O.L.)