Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect X8 from the PCB
Measurement:
Check for continuity (zero resistance) between pin 5 (grey) at the disconnected plug to the grey wire at the low voltage terminal block.
Check for continuity (zero resistance) between pin 4 (black) at the disconnected plug to the black wire at the low voltage terminal block.
Inspect harness and connectors for good overall condition.
Check for continuity (zero resistance) between pin 4 (black) at the disconnected plug to the black wire at the low voltage terminal block.
Inspect harness and connectors for good overall condition.
Isolate as per TOPs P4
and refit as necessary