Vents wont change from defrost

[rthomp]

I have a 2003 Yukon. The HVAC controls are set for AC or heat to come out the dash vents but it just comes out the Defroster. When you start the vehicle, you can fell the air come out the vents for a couple of seconds then it returns to the defroster. This happens no mater what the controls are set on. anybody have any ideas what might be going on or have a fix?
Thanks!

 

[Rangel]

sounds like your blend door is stuck, or gears are stripped. I just had to fix my rear heater. the door was stuck some kind of way, the actuator was still good though.

 

[rthomp]

Thanks, That's a start. Ill check that next weekend...

 

[nuc_meltdown]

read through this. there is a relearn process. not sure if that's what yours needs, but there is other info in there. Have you had the battery loose for any reason lately? I'm finding that doing that makes these trucks go nuts!

http://www.tahoeyukonforum.com/forum/showthread.php?t=17741&highlight=blend+door