96 yukon no AC thru dash vents

ac seems to be working ok, just cant get air up thru vents. with ac and recirculate buttons off......air temp and vent controls work correctly. Turn on ac and the air speed/pressure increases and you can hear/feel cold air blowing out at bottom heat vents, but does not change location when vent control swith is turned.......turn ac off and vent control blows just fine at whatever vent u select.....any ideas?

mine does the same thing but after 20 secs or so a door or vent shaft closes and cold air comes out vents, i think its the defrost switching back over to ac. try going back and forth from ac to defrost and maybe the door will open or close fixing the prob.

Hi, you may have to service the trap door.
Take care, Eggert :bananasmi

For those of you who may experience similar problems, mine ended up being the HVAC control module.....i spent 25 bucks on the alldata subscription, lots of useful info but still a wild goose chase.....all tests checked ok due to problem being interrmittent, it would work a few day then not again........anyway after a half day of testing/diagnostics i finally got frustrated and started probing the control, i shorted somethin, it zapped, worked momentaririly then all shut down. IE i decided for myself(having broke the part) to go get a new one for $ 212 not knowin for sure whether my problem would still exist or not, luckily the new control fixed all the problems. A day shot and $ 240 poorer but prolly still less than the labor would have been. I just spent 800 a few months back on compressor so hope this fixes the cooling for a while, still doesnt seem to cool as well as it did before.

'01 Yukon XL: Rear heat and ac don't work. Checked all related fuses, and they are good. What should I check next?

mine does the same thing sometimes, the fan is blowing like hell, but nothing coming out of the dash vents. i did discover that the air is blowing hard out the little vents pointed sideways at the front windows. looks like i need to search how to service the trap door