AC will only blow out the defrost

[Txstang1]

90 Foxbody. Was working fine last summer, put it on heat it comes out the bottom, defrost it comes out the top, AC it comes out the vents.

THis year, nada....defrost only. I've checked the vacuum lines, all appears ok.

Anything else I should be looking at ?


Thanks


Also, No matter what setting the AC controls are set to, that flapper door beneath the glove box does move. could that be related to the issue?

[dumpycapri85]

Either the control swithch is leaking vacuum or the actuator is bad . All those controls work off vacuum and it doesn't take much of a leak to make them not work .

[92lxstang]

Double check the vacuum line that runs along the firewall in the engine bay. Mine did the exact same thing once and there was a small crack in the vacuum line.

[TENGRAM]

Double check the vacuum line that runs along the firewall in the engine bay. Mine did the exact same thing once and there was a small crack in the vacuum line.

^^^this. 99% of the time this vac line has broken or come disconnected.

[Txstang1]

Ok, the one that runs along the firewall that come off the vacuum tree label "a/c" ? That one is good.

On the back of the control panel, the black vacuum line had pulled out of the back of it, so I stuck it back in there. I bet that one is not sealing good. Should I use some silicone or super glue maybe ?

[Txstang1]

Ttt

[greenbullitt]

Ok, the one that runs along the firewall that come off the vacuum tree label "a/c" ? That one is good.

On the back of the control panel, the black vacuum line had pulled out of the back of it, so I stuck it back in there. I bet that one is not sealing good. Should I use some silicone or super glue maybe ?

it usually doesnt take much to seal. I think i have a spare harness if you need one, but im a drive for you, maybe a track meeting...check the yellow line under the dash too