Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove connector CN3 from the PCB & electrical connector from gas valve
Measurement:
Measure the resistance as follows:
Blue wire on CN3 to pin 1 on the gas valve connector.
Blue wire on CN3 to pin 5 on the gas valve connector.
Brown wire on CN3 to pin 4 on the gas valve connector.
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.
Are the harness checks satisfactory?
Blue wire on CN3 to pin 1 on the gas valve connector.
Blue wire on CN3 to pin 5 on the gas valve connector.
Brown wire on CN3 to pin 4 on the gas valve connector.
Expect continuity / zero resistance on each test.
Also visually inspect the condition of the harness.
Are the harness checks satisfactory?
Isolate as per TOPs P4
and refit as necessary