05 1500 5.7L 88K
I had this issue for the first time about a month ago. When I go to turn on either the heat or AC, it does not turn on. Later that day it started working normally again. Yesterday I went to turn on the AC and the same thing happened; no air. Any suggestions?

 

Most likely, just need a new motor, but you can verify ahead of time by pulling the connection block at the fan and checking for voltage to the fan first, could also be a number of other things too, but its best just to make sure its not a bad motor, or possibly resistor pack, (these are what change the fan speed).

 

I went ahead and replaced the blower motor. Hopefully this will solve the issue, but I won't really know unless the same issue occurs again. Thanks for the help.