Your not the first person to
Your not the first person to have this problem. More than likely it is one of the blend doors in your A/C system duct work. The problem is one of them is a lot of work to replace. These blend doors regulate mixing cold air and air from the heater core but with a malfunction they can allow to much warm air through the duct system. The '08 has separate front passenger temperature controls so the warm side blend door may be the problem. At any rate, this is not normal and your dealer knows it.