Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Disconnect connector CN4 from the right hand PCB

Measurement:

Test 1:
Measure the resistance between the red and blue wires
on connector CN4.
Expected resistance approx. 1 Ohm.
Please remember to take into account the
resistance of your probes when carrying out this test.
Test 2:
Measure the resistance between the red wire on
connector CN4 to a suitable earth point.
Expected resistance greater than 1M Ohm.