Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect fan connector ST5 from the PCB
Measurement:
Test 1: Place the black test probe on the brown wire and then measure the resistance to each of the test points listed in the table below at the disconnected fan connector ST5.
Resistances should conform approximately to the table below.
Test 2: Measure the resistance between each of the wires to a suitable earth point.
Expect 1 Mohm or greater on each test.
Are the resistances as expected?
Resistances should conform approximately to the table below.
| Test Point | Resistance |
| Brown - Purple | 1 Mohm or greater |
| Brown - Orange | 1 Mohm or greater |
| Brown - Yellow | 1 Mohm or greater |
| Brown - White | 1 Mohm or greater |
Test 2: Measure the resistance between each of the wires to a suitable earth point.
Expect 1 Mohm or greater on each test.
Are the resistances as expected?
Isolate as per TOPs P4
and refit as necessary