Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance

Measurement:

Disconnect Fan DC controller connector
marked H3 on the main PCB.
Test 1:
Measure resistance across the live (brown lead)
and neutral (blue lead) connection on the connector.
Expect approx. 44 Ohms.
Test 2:
Measure resistance across the live
(brown lead) and a suitable earth point.
Expected resistance O.L or greater than 1MOhm.