W.I indicator / pressure switch
If you need a new one, here is a link to our on line shop:
http://www.ukanfixit.co.uk/content/di...
Although the Whirlpool dishwasher F4 error code is "not draining" it is actually a time out of the electronics, if this pressure switch does not reset as the sump drains the water away, F4 error will be displayed. The same error as if the pump was restricted in some way. Two different faults but the same dishwasher F4 error code.