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

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?