Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the connector from the stepper motor

Measurement:

Measure the resistance between the pins 1 to 6 on PCB connector X7 to
the corresponding pins on the stepper motor harness (3 pins on each side).
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.