Set Appliance State:

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

Measurement:

Check the resistance of the disconnected harness (4 wires)
and the PCB connections.
Blue to blue,
Green to green,
Black to black,
Red to red.
Continuity (zero resistance) should
be measured on each wire.