Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts Set meter to measure AC Volts
Remove outer panels and lower the front facia to gain access to the programmer wiring connections
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the voltage between the brown and blue wires on the 4 pin connector at the back of the programmer.
Mains voltage should be present.