My son just got a 2009 FX4 It was a demo with 3300 miles and he had it about a week and noticed the ac vents on each side of the steering wheel had hardley any air coming out . The others are fine . The mechanic wants to change the ac tubes under the dash . He thinks somthing is blocking the air . he wont say what he thinks it is .Unless somthing is not opening this sounds weird . Anyone had a problem like this? Thanks for any help.