the heat will not blow when the truck is cold, what I mean is the blower will not turn on. if you leave the truck in heated garage for a day, it will work until you park the truck outside again. took it to dealer and they want to replace the whole blower motor. anyone does this? how difficult to change that? not familar at all with 4th gen stuff? It has nothing to do with the auto on feature of the truck we have that off. seems like it is happening when it is below zero stuff..