How to change speed on my windshield wipers?

I have a 2003 Ford Windstar. I turn the wipers on high, but they're really slow. I can't drive in the rain, period. That's how slow they are, on high. What could it be and what can I do?

Your Ford wipers should have three setting: intermittent, low and high. Are you sure you don't have them set on intermittent?

I'm sure I can crank the dial all the way and they go the same speed. I've even looked to make sure it was that.