Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove plug from diverter valve motor

Measurement:

Check for continuity (zero resistance) of each of the
5 wires running between X4 and the disconnected plug.
(refer to table below for which pins to test between for each wire).
Inspect harness and connectors for good overall condition.