Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect plug for pins 10-15 from the PCB

Measurement:

Test 1:
Measure the resistance between the two
violet wires (10 & 11) on the disconnected plug.
Resistance should be approximately 4.2 kOhms.
Test 2:
Measure the resistance between each of the violet wires
(10 & 11) on the disconnected plug to a suitable earth point.
Resistance should be greater than 1MOhm on both tests.