AC only blowing out defrosters

[Vic710]

AC is only blowing out defrosters in the front. Rear AC works fine.
Temperature control is working, I have both hot and cold air with no thumping noise when I turn the control knob. So it doesn't sound like the blend door. I checked the vacuum lines behind the vent control knob and behind the glove box and all connections seem ok. I can push the door open that blocks the front vents but they won't open on their own. Not sure if this is connected but 4x4 low won't engage. I'd appreciate any suggestions.

 

[Vic710]

Found the problem, it was a vacuum line under the hood.

 

[Davidm53]

General location of the line? Incase we have the same issue.

 

[rpack82]

I have the same issue. I checked some vac lines behind the glovebox and did not see any issues.

@Vic Where under the hood did you find the line?

Thanks.

 

[BrooklynBay]

Welcome to this forum! Follow the vacuum lines off of the main vacuum tree. One of them goes into the hard plastic color coded line with a rubber boot on the end.

 

[Vic710]

Follow the two lines that go out under the glove box just above the floor on the passenger side. Mine were a black and grey line. You'll see them on the back fire wall under the hood. A few feet out there was an accordian type of rubber connector, that's where the leak was.

 

[jabberwocky47]

AC is only blowing out defrosters in the front. Rear AC works fine.
Temperature control is working, I have both hot and cold air with no thumping noise when I turn the control knob. So it doesn't sound like the blend door. I checked the vacuum lines behind the vent control knob and behind the glove box and all connections seem ok. I can push the door open that blocks the front vents but they won't open on their own. Not sure if this is connected but 4x4 low won't engage. I'd appreciate any suggestions.

How were you able to check the vacuum lines behind the vent control knob? Did you have to remove the dash?