Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Disconnect plug to APS
Disconnect plug to APS
Measurement:
Check for continuity (zero resistance) of each of the three wires running from the APS to pins 10, 11 and 12 at M3 on the PCB.
Inspect the wires and connectors for good overall condition.
Note:
Some or all of the pink wires on M3 may not be present depending on the exact model you are working on.
Inspect the wires and connectors for good overall condition.
Note:
Some or all of the pink wires on M3 may not be present depending on the exact model you are working on.
Isolate as per TOPs P4
and refit as necessary