Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Disconnect connector marked J4 from the
main PCB and make safe
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Mains reset switch ON
Does fan start to run at high speed?
Note:
If fan still does not run do not reconnect J4.