Have a 2004 Silverado, the problem is that the fan blows great but when I switch to #5 setting it quits blowing. Had this problem a few weeks ago but it always came back on. Now no high speed. Sucks in AZ when its 110 outside. Any Thoughts

 

Sounds like the switch.

 

probably the blower resistor and its plug melted..look under the right floorboard and see if she's burnt