Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector X1 from the main PCB
Disconnect inline connector running to the main PCB

Measurement:

Check for continuity (zero resistance) between the ends of both the blue and brown wires running from X1 (right hand wires, refer to picture) to the corresponding wire (refer to picture) at the inline connector.
Inspect harness and connectors for good overall condition.
Note:
On the inline connector use the connections with a single wire
(as arrows indicate) as this also proves the link is not damaged.