My dads friend with an 04.5 is experiencing his blower not working anymore. The way he described it to me was it used to work when he would go and start the truck up, but after you start it it would stop working, and now it doesn't work at all. He said this all started after he replaced the thermostat, but I doubt that has anything to do with it. I will not that he did replace his resistor about a month or 2 ago so that is not the problem. Any help is appreciated because we are all in the dark. Thanks!

How about the blower motor, sometimes they go hand in hand.