vent for defrost stuck open

[murfthsurf]

I have a 2001 gmc 3500. My controls for the operation of the vents does not work no matter where i turn the control the vents stay open in the defrost position and will not change to the vents. Is this system electrial control or do i have another problem

[gmtech4]

electric,disconnect the battery and wait abit ,reconnect ,turn key to on maybe (cant remember if its required),you can then hear the actuators doing their own little relearn ,should be ok after that ,if not ,have it scanned and diag'd

[txab]

A re-calibration may fix you up. Try disconnecting the battery again for a few minutes. Reconnect it. Then turn the key to the on position, but don't start. Don't touch the HVAC controls. Let them do whatever that want to do. Air flow may change outlet points during this time. Wait about 1 minute. Turn key off. Sometimes opening and closing the door can make a difference as the vehicle controls see this as "cycle" completion. Next start the vehicle and drive it a short distance and see how it performs.

[gmtech4]

i said half of that first !!!!! lol

[murfthsurf]

any other ideals it tried it about 3 times and still not working. does anyone know where i can get the wiring stymatic from may be a bad relay fuse or something elese

[gmtech4]

alldata.com or

 

check all HVAC and HTR fuses in underhood fuse block and left i/P fuse block,

 

open owners manual,its in there for the fuses as well,

 

or as i said .,take it in,its a module and has codes

 

good luck,,,not sure if cheap code readers will read HVAC