A/C blower motor problem

I took the 69 Valiant down to get the a/c charged again yesterday. Had it charged last year and when I uncovered it this year the a/c didn't work. I figured it had a leak. The mechanic charged it and put dye in it and told me he didn't see any leak. Told me to check it if it gets warmed and look for the dye. It was blowing at 40*. On the way home I noticed the air wasn't blowing as hard as I thought it should. When I got home I played with the switch some and noticed that it didn't matter which position you put it on, it blowed at the same speed. I even turned it all the way to the left and it still blowed the same. I had to push the button to get the blower to stop. Now I haven't messed with this or had a chance to get into it yet, but I am thinking it is a switch problem. The switch has 2 positions on it. I plan on getting it in the garage when this Nissan goes home and look at it. I don't know if a wire is crossed or whether the switch is bad. What does it sound like to you. Thanks,Bill