Contour Enthusiasts Group Archives Forums General Troubleshooting A/C only blows on high

I have a 98 contour SE, the A/C works great! It is cold as ice and blows hard on max. Yesterday, while driving, I switched the A/C form high to low, and it turned off. The A/C has four modes of blowing......low, intermediate, medium, and high. It only blows on high.

Could this be electrical? Vac line problem?

Thanks for any help!