A/C changing from front panel to defrost

[sammy2966]

The a/c air is changing from the front panel to the defrost and then it changes to front panel when it pleases, the control button is not changing to different areas (ex. bottom, defrost, front panel, a/c or max a/c) when i change the temperature from cold to hot, sometime it stays hot even when I change it back to cold. Could someone help me with this issue?

 

[Clusterpup]

Sounds like you have a vacuum leak. Does it change to defrost when you press the gas?

 

[-junior]

i have the same issue on my 05 xlt sammy. when on "max ac" the vents will blow through all fronts for a minute, then switch to just defrost. not sure what causes it, i just leave mine set to "ac"

 

[-junior]

After doing a little research came up with a couple threads that might help some people.

Looks like this is a common problem on the vacuum controlled AC in Fords

Here is an F150 post about the same issue, and a good post from Clusterpup with a pic. I'm going to check out my hoses today, does anyone have a good pic of the AC line, or a description of common failure points similar to those f150's for the sport trac....UPDATE, after a little more research my problem is fixed. Check out this link to the 2nd gen forums. There is a canister under the glove box with a white vacuum line connected off a t-fitting. Looks like someone kicked mine off. Just had to plug it back in and now the "max ac" stays on panel vents instead of switching to defrost.

http://www.f150forum.com/f10/ac-max-selction-intermittantly-changes-defrost-51243/

Great pic from Clusterpup:
http://www.explorerforum.com/forums/showthread.php?t=316750&highlight=ac

2nd Gen forum post:
http://www.explorerforum.com/forums/showthread.php?t=192842

 

[Lil Blue]

Loss of vent function

Thanks for the 2nd gen link from 2007. Ir identifies my problem with the vents. Will let yall know if it work for me.
Thanks