I was kind of figuring that my intermittent wiper issue was due to a bad control module (the one at the base of the steering column). I had read where that could be a source of those kinds of issues. And since they are apparently unobtanium, I had just written it off and was thankful for just having "high" and "low". But yeah, no idea why just having the washer motor connected made it work, but somehow it did. I should also add that there's definitely been some "backyard rewiring" done on mine by POs, so it's also possible that it's due to that.