Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove 6 wire connector from the PCB

Measurement:

Measure the resistances between the black, red and green set of wires from the PCB connector to the terminal block.
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.