Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove diverter valve connector from PCB
Remove the two wire connector that leads to
the On/Off switch from the PCB

Measurement:

Test 1:
Measure the resistance between the purple and red wires at the diverter valve PCB connector.
Expect 1 MOhm or greater.
Test 2:
Measure the resistance between the red wire on the diverter valve PCB connector and the red wire on the on off switch connector.
Expect 0.8 MOhm or greater.