Hello and thanks for donating
Intermittent conditions are always the toughest to repair. In this case, it is actualy relatively simple. You can rule out wiring pretty easily here because if it were grounding out than they would come on even when the switch wasn't activated or they just wouldn't work at all and blow the circuit fuse. The only thing left on the circuit for wipers that include both washer and wiper functions are the wiper switch on the dash and the wiper motor module. In this case, the wiper motor module is the most likely culprit because if the switch were to be faulty than it wouldn't effect the wipers when the washer button was pressed because the washer part of the switch has a different wiring to it. Replacement of the wiper module is suggested. I have attached a copy of the wire diagram for wiper system below..
Saturday, August 29th, 2020 AT 1:37 PM