Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect 2 pin connector from the programmer

Measurement:

Check for continuity (zero resistance) between the blue wire at the disconnected plug and pin 4 (blue) at connector X400 at the PCB.
Check for continuity (zero resistance) between the white wire at the disconnected plug and pin 7 (white) at connector X400 at the PCB.
Inspect the harness for good overall condition.