I recenrtly purchased a 92 legacy and until the other day never needed to use the wipers on high, when i switched them on high they shut off. They work on intermitant and low as well as the one quick pull to clear the windshield. They also work fine when you use the washer button. Is this common and is there an easy fix for this? Any help is appreciated.

This isn't a real common problem. The switch contacts for the high speed control would be my first suspect to check.

Yes. Check the control stalk for the wipers. That is where all the circuitry for the wipers is.