i have noticed since the day i picked up my truck that my hvac does allot of clicking and clunking. as a mechanic it just seems off to me but at the same time it doesn't make noises that seem like the blender doors are getting stuck or the motors are skipping. i haven't had time to go check out another one at a dealer so i figured id ask some of you if you have noticed the blend doors being a little noisy and put my concern that there is something wrong. the noises seem to happen when the temp either reached equilibrium or is turned hotter or colder. it could be from changing the vent orientation well now that i think about it i always run it in auto ill have to give that a try next time im in the truck.