Hi Richard. Yes that is what I thought. A few months back now, prior to having the wiper single wipe park problem. I was getting every now & again a dead short on the washer pump motor feed. All the wiper functions were fine. Just trying the washer would blow the 10 amp fuse. I’d fix it but not knowing how, I even changed the wiper stalk, with one obtained from E-Bay. Finally I found that the park & motor assembly on the wiper motor was allowing the plug to creep back about 2 mm. Not a lot but was slightly loose. Pushing it home & using a clip arrangement solved the problem. I could reproduce the fault just by easing the plug back, but I could not see how the short was occurring. In my case a short but maybe the OP has an open circuit.
As you say sometimes the wireing diagrams are no help at all.
