Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove PCB from appliance
Disconnect plug for pins 6-9 from the PCB

Measurement:

Test 1:
Measure the resistance between the two
orange wires at the disconnected plug.
Resistance should be approximately 70kOhms or greater.
Test 2:
Measure the resistance between each of the two
wires and a suitable earth point.
Resistance should be greater than 1M Ohm on both tests.