04 3500 4x4 4door . the aircondition blows on high for about a hour then the air coming out of the vent is little or like the fan was turned to low. I can still hear the the fan blowing high in the dashboard but little air is coming out of the vent. When the truck or the ac is turned off for a little while it workes fine for a while then same-o again. HELP-PLEASE. 
