Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove electrical connector to DHW temperature sensor
& connector X16 from the PCB
& connector X16 from the PCB
Measurement:
Measure the resistance across each of the wires to the DHW sensor (red and black).
Expect continuity / zero resistance across each of the wires.
Also visually inspect the condition of the harness.
Is the harness satisfactory?
Expect continuity / zero resistance across each of the wires.
Also visually inspect the condition of the harness.
Is the harness satisfactory?
Isolate as per TOPs P4
and refit as necessary