Why does the defroster vents only work no matter what setting the selector is set to?
No matter cold or hot, the air only blows through the defroster vents, no matter which
setting is selected.
Sounds like you mode door actuator needs replaced.
I believe your model has three ac/heater door actuators . 1) is for mode door 2) is for blend door 3) is for recirculate door
Check for a broken or disconnected vacuum hose coming from the intake manifold. If the system loses vacuum for some reason it defaults to defrost for safety reasons. HTH. -Jim
http://www.heatertreater.net/videos.html#chevy --- check this out it may help. There are also several videos on you tube.
Where do I find the mode door actuators?
Looking for a Used Yukon XL in your area?
CarGurus has 13,079 nationwide Yukon XL listings starting at $1,750.
Search GMC Yukon XL Questions
GMC Yukon XL Experts