Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Measurement:
HW Tap OFF.
Measure resistance between connectors C3 and C7, PCB, track-side, top left.
Resistance should be approximately zero ohms.
Measure resistance between connectors C3 and C2, PCB, track-side, middle left.
Resistance should be approx 50 ohms.
HW Tap ON.
Measure resistance between connectors C3 and C7.
Resistance should be an open circuit.
Measure resistance between connectors C3 and C2.
Resistance should be approximately zero ohms.
Measure resistance between connectors C3 and C7, PCB, track-side, top left.
Resistance should be approximately zero ohms.
Measure resistance between connectors C3 and C2, PCB, track-side, middle left.
Resistance should be approx 50 ohms.
HW Tap ON.
Measure resistance between connectors C3 and C7.
Resistance should be an open circuit.
Measure resistance between connectors C3 and C2.
Resistance should be approximately zero ohms.
