I read a comments about the vent situation with a Frontier truck blowing warm air. I guess there is not a fix for this? I just purchased a used 2001 Frontier and I have noticed this as well. I also noticed a noise when the truck is moved forward or backwards, it is only made during the first couple of feet. At that, the noise is not heard again, unless you turn off the vehicle and start it again and move a couple of feet. The dealer said that this is the anti-lock system doing a check. Has any one had this occurrence?