Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
Gain access to PCB (use Insulation Mat as required)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow fan fault code to occur.
Measure the voltage between the brown wire marked 13.4 and the blue wire marked 13.5 within 2 minutes of the appliance entering fan lockout.
Mains voltage should be present.
Note:
After 2 minutes the voltage to fan assembly will no longer be present, if required reset the appliance and allow it to re-enter fan lockout to confirm the outcome of the test.