Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove diverter valve head by removing retaining clip and lifting up
Disconnect the leads from the actuator

Measurement:

Test 1:
Measure the resistance between red and purple.
Expect either approximately 8.3 kOhms or open circuit.
Test 2:
Measure the resistance between red and grey.
Expect either approximately 8.3 kOhms or open circuit.
Note:
Colours are marked on the diverter valve head.