Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove the plug from connector X9 on the Main Driver board

Measurement:

Measure the resistance across the wires on the end of the plugs.
Is resistance between:
Purple and Yellow connections approximately 10kohms
Purple and Pink connections 0 - 10kohms
Replace plug into X9 after measurements are complete.