Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Gain access to PCB (use Insulation Mat as required)
Disconnect 4 wire plug from the fan
Disconnect connector X401 from the PCB
Disconnect 4 wire plug from the fan
Disconnect connector X401 from the PCB
Observation:
Check for continuity (zero resistance) between the ends of each of the 4 wires of the low voltage fan harness:
Brown at fan to brown at X401 (pin 3)
Blue at fan to blue at X401 (pin 4)
Black at fan to black at X401 (pin 5)
Green at fan to green at X401 (pin 6).
Inspect the length of the harness and the plugs for good overall condition.
Brown at fan to brown at X401 (pin 3)
Blue at fan to blue at X401 (pin 4)
Black at fan to black at X401 (pin 5)
Green at fan to green at X401 (pin 6).
Inspect the length of the harness and the plugs for good overall condition.
Isolate as per TOPs P4
and refit as necessary