Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove air intake housing and fan assembly
Remove PCB from fan assembly (For instructions click HERE)

Measurement:

Test 1:
Measure the resistance across the fan
motor terminals on the left hand side.
Resistance should be approximately 60 Ohms.
Test 2:
Measure the resistance from either of the fan motor terminals to a suitable earth point.
Resistance should be greater than 1M Ohm.
(OL is acceptable because it is greater than 1Mohm)
Test 3:
Check that the fan spindle turns freely and that there is no sign of damage or water ingress in the fan.
Note:
Instructions supplied with fan PCB may suggest a 2nd resistance test, this test is unnecessary and the resistance given is wrong.