Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect X2 from the PCB
Pull X1 back slightly to expose test points

Measurement:

Check for continuity (zero resistance) between pin 1 (red) on X1 to pin 6 (black) on X2.
Inspect harness and connectors for good overall condition.