So I bought a 1997 Jeep Wrangler about a month ago and one of the problems was the blower for the heater was not working. Going through this forum I narrowed it down to 3 things. Since it wasn't working at all and not just in certain settings I ruled out the relay. I figured I might as well get the big thing out of the way and I replaced the blower motor. Well that didn't work. I went back to maybe it could be the relay and I replaced that, still didn't work. Well it could be one other thing and that is the switch. Since the switch was missing the knob I figured I might as well order the switch and the knob. Easy enough replacement and guess what, it still didn't work.
Now I am really stumped and have no idea what it could be until it dawned on me. Let me check the fuse. Guess what, the fuse was missing! I grabbed a battle spare and threw it in there and my blower fan roared to life. So the Dumb Move award for 2012 goes to me.