My Creda T622Cw only works on the low setting?

My Creda T622Cw is not producing any heat from the high setting only the low setting . That should mean that the thermostat is OK. I have had it looked at and was told both heating elements check out ok. Apparently there is no signal along the orange wire from the control unit ? and that needs replacing. Need a part number to find it on spares sites and a part list or parts diagram to find the right part

Everything else works fine. It tumbles. Timer fine. Water container is empty. Condenser & filter clean and clear