Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance

Measurement:

Test 1. Measure for resistance across the terminals 1 and 2 at the timer.
Expected resistance approximately 4.5kΩ.
Test 2. Measure for resistance across terminal 1 to a suitable earth.
Expected resistance greater than 1MΩ (or O.L)