Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove connector from thermal fuse
Disconnect inline connector to thermal fuse if it has been refitted after previous test

Measurement:

Measure the resistance of each of the wires in the harness to the thermal fuse.
Expect continuity / zero resistance.
Also visually inspect the harness and it connectors for good general condition.
Are the resistances measured as expected and is the harness in good condition?