Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect connector ST15 from PCB

Measurement:

Test 1:
Measure for resistance across the connections of disconnected
connector ST15. (Ensure good connections are made)
Resistance should be approximately 160 Ohms.
Test 2:
Measure for resistance between the brown wire at the
disconnected connector ST15 to a suitable earth point.
(Ensure good connections are made)
Resistance should be greater than 1M Ohm.