I am having a problem with my rear climate.... Like I have noticed that when I am sitting parked somewhere it is working just fine... But when I take off and get going down the road, reach back and feel the vents.. nothing is coming out of them weather I have it turned on heat or air.. I turn it to level 3 with the front knob and with the back controls (with the front on rear mode of course) and still nothing when driving down the road.. I can however hear the blower running in the back of the truck.. Its really strange and I cannot for the life of me figure out what is causing this. It has only had one other owner and he has taken great care of it I know.. and I take great care of it as well.. I just don't know what is causing it not to work while driving down the road its like a trap door of some sort falls shut and cuts off circulation or something??? thats what happened in my '91 Sierra all the time but I didn't know if these new models had that type of operation in them.. Any suggestions or ideas would be appreciated thanks!