I have the same problem. No blower on any speed or position. Then it will just start randomly and keep working until I turn the key off. This morning when I got to work I pulled the fuse cover on dash to check for power at the fuse. It was good. What I found was a bad connection on the output side of the fuse. If I push sideways on the fuse the blower will work. Push the other way I can make it stop. Try the wiggle test starting at the fuse and work to the resistor and blower. My truck is an ex fleet truck for where I work. The main reason for it's removal from service was the blower not working. Someone had put a fuse tap on the blower fuse. It looks like that damaged the terminal in the fuse block. I tightened up the terminal end (bent it with a dental pick) and so far it seems to be fixed. Don't overlook the simple things, and never underestimate the damage and problems that a "mechanic" can cause.