Set Appliance State:

Set Multimeter to Resistance Set meter to measure resistance
Isolate Mains Power to appliance as per TOPs P4
Separate the potentiometer/harness assembly at the inline connector

Measurement:

Measure the resistance between each wire on the separated potentiometer/harness assembly.
Expect continuity on each test.
Also visually inspect the condition of the harness checking for any damaged insulation.