Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove both orange wires from the modureg

Measurement:

Test 1:
Measure the resistance between the two terminals of the modureg.
Expect approximately 125 Ohms.
Test 2:
Measure the resistance between one of the terminals of the modureg and a suitable earth.
Expect a resistance of 1 Mohm or greater.
(O.L is acceptable because this is greater than 1 Mohm)
Are the resistances measured as expected?