Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove fan control connector from fan assembly

Measurement:

Measure the resistance between pins 10, 11 and 12 on connector X8
to the corresponding pins on the fan control connector.
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.