Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect connector X23 from the PCB
Measurement:
Measure the resistance on the harness connections as below
The resistance should conform approximately to the table below:
The resistance should conform approximately to the table below:
| Leads | Resistance | Blue-Brown | 33Kohms |
| Green-Black | 3.4Mohms |
| Brown-Black | 16Kohms |
| Blue-Black | 50Kohms |
Isolate as per TOPs P4
and refit as necessary