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
For easier access unclip relay and position as shown

Measurement:

Check for continuity (zero resistance) between each of the black wires at X2 to the corresponding wire at the relay.
Inspect harness and connectors for good overall condition.