Hey Folks!

The wife and I went out for lunch yesterday and I ran into some odd stuff with my A/C on the way home.
<O</O
<O</O
I had the A/C set and to blow out from the front dash, after a couple moments I noticed the noise level of the A/C blowing change and there was no longer any air coming from the front of the dash but rather from the top as if I turned on the defroster for the windshield.

I tried multiple settings both with and without the rear climate control running, same problem. It would intermittently switch to blowing from the defroster, and sometimes it would switch back on its own.

WTH!?<O</O


P.S. - I'm leaving for CA later this week. If I can't figure out a quick and easy fix I'll have to take to shop when I get back.

 

Check all your vacuum lines. My F250 did this once and it was vacuum related - one of the hard lines came unseated from a coupling.

 

Mine did this a few times once it was the vacuum pump gone bad, once it was a fuse.

 

As others said, you have either a vacuum leak or a problem with the vacuum pump.

 

I don't think it's your vacuum pump, you have the big 10 cylinder vacuum pump on your Ex Chad.
It does sound like a leak in your vacuum lines somewhere, HVAC defaulting to the defrost position is a classic sign of a vac leak.

 

Probably you vacuum 4wd actuator on the passenger side under the hood, may look ok until you unbolt it. They tend to rot/blow out in the back, 4wd may still work fine even if its bad.

 

Heh heh didn't read the fine print... But vacuum leak is still suspect.

 

Certainly vacuum. Mine just started the same thing. When on the throttle it switches to defrost and light on the pedal vacuum builds enough to compensate for my vac leak and turn the vents back on. Haven't had time to troubleshoot it, but the Auto 4wd most likely won't lock in properly either until you fix it, if you still use it. If you find the leak please post so you can give me a place to start on mine too.

 

2000 Excursion with the exact same problem. Time to start checking for vacuum leak.


just stumbled upon this web page which should help tremendously...


http://www.justanswer.com/ford/3ink5...elorating.html#

 

GREAT post Nut
WELCOME to the world of XXXs Please add your general lo-cal to your profile

 

This...


...plus this....


= Problem Identified

Stewart

 

Many thanks to everyone for the info on fixing the defrost problem.
My turbo 4wd ex started blowing ac from the defroster yesterday WTF?
so come here to the trusty forum and after I got the info started looking for the leak and the pump running all the time. Replaced the lines to the hubs which had rotted and leaking,still blowing from defroster. I didnt wanna screw around cause its 96 here in Texas. Bought a new vac pump and esof .
Then before I installed them I found a tiny vac line that went to a diaphram I guess on the heater box? It had snapped in two....used a heatshrink electrical butt lol...worked.....so anyhow replaced the pump and esof and BOOM the AC is working from whatever vent I want!! It was prolly the lil vac line to that diaphram...but I now have 4 wheel drive and cool AC
THANKS to ALL Wash

 

Hey Guys,

So this line was off. It's the only thing I could find. It seemed to be the right place to plug it in, wanted to check with you folks to see if this looks right/matching your trucks?

 

Yes, that is where it belongs

 

Here you go....