Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Remove Front Panel of Electrical Control Box

Measurement:

Depress Ignition Switch
Measure short circuit resistance across Grey and Beige wires of Ignition Switch.
Release Ignition Switch
Measure open circuit resistance across Grey and Beige wires of Ignition Switch.