Is this something not covered under warrantee? Or you just wanted to fix yourself? I just had the same thing happen where I filled up an entire gallon of fluid and next day the low fluid light came on. Before this the front sprayer worked but the rear sprayer did not. Does the leak occur inside and get the carpet wet?
The fluid was leaking out of the crappy plastic line, under my rubberized flooring and the rear seat, then running down into the rear passenger side foot well...and then dripping onto the ground (and when I was finding odd puddles I at first had no idea what was going on). When I finally realized what was going on, I pulled the rear seat, rubberized flooring, etc. and traced it to the cheap plastic corrugated line. I imagine it would have been covered by warranty, but I'm sure Ford would have kept my Bronco longer than it needed to be there and there was probably a long wait at the time for parts. I ordered the hose and installed it without any issues. I hade zero idea why Ford didn't simply use a 3-foot piece of rubber hose (the rubber hose is probably cheaper).
