[1971LT1SWBPOSI373]

My truck has 3 fan speeds, lo, med, and high. Sometimes I have to push the lever over to the extreme right to get it to blow on high. There is a switch on the back side of the control panel that is notorious for going out (3 speed switch) and is pretty easy to change, and available from any of the truck places. I guess the first thing to check would be to see if you can get it to blow in the high position, or jumper the switch to verify it's bad.