Set Appliance State:

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

Measurement:

Measure voltage between N and the brown wire in the Summer/Winter Switch.