Moderate windshield wiper speeds not working.

Moderate windshield wiper speeds not working. I have a 2010 Ford Escape XLT V6 4WD, and some of the windshield wiper speeds do not work. Only the moderate speeds. I have slow full speed, but none of the others work. I've been able to get by, with treating the glass with Rain X solution but I really want to have all my speeds. I think it's the switch, because it does work when you use the spray fluid button.