Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Remove the diverter valve actuator from the diverter valve body

Observation:

Check for free movement of the diverter valve spindle.
It should be possible to depress the diverter valve spindle with a fairly small amount of pressure.
The HW position is when the pin is fully raised.
When pushed in the pin should return to the raised position when released.

Note:
For clarity the graphic shows the valve removed but it is possible to check the spindle with the valve in situ and the actuator removed