Air coming from defrost vent not front vents???

[AZDENALI07]

Has anyone had this problem and can tell me what the fix was? I try cycling it thru to front vents, foot vents and still only comes thru defrost vent. I am not trying to pay GM dealership high prices if I can fix myself. Thanks in advance for any help you can give.

 

[sumo]

sounds like a Blend door actuator , Its gonna require Dash Removal to get to it.

 

[zieglerj-pdm-specialist]

Sumo is right,but the blend door actuator usually only adjusts the cold air from the warm air. The vents not changing could be a vaccum hose. It may be leaking, damaged, unhooked or plugged. Look under the hood up by the firewall to see if there is any hoes unhooked from a T fitting or just not hooked to anything. My 95 Blazer would be on defrost but it would blow out the vent below and when I went up a hill where the tranny dropped down to a lower gear the air would blow out the defrost because the higher RPM would boost the air and it would change the vents to the right setting, when it would settle out it would drop back down to the floor vents.. I found a hose that was not connected solid and it would leak. Im not saying that is the problem because mine was a 95 and yours is a 07 alot has changed in 12 years. Just trying to help.

 

[AZDENALI07]

Thanks for the time and help. Its weird b/c sometimes it wont do it for weeks then i will turn it a/c or heat and just comes out of the defrost vent. I will look for leaks in the vacuum hoses and if i cant find anything i might take it to Pep Boys since they give diagnoses for free but i think it might be hard to trouble shoot if not consistanly failing. Will let you know what I find or what happens incase anyone else in the forum might have same problem.

 

[zieglerj-pdm-specialist]

I hope Pep boys can diagnose it for you but could you let me know if it was a vaccuum hose. I would be interested to know.