A/C Recirc Door Vacuum Problem?

[dlyoung1]

Just finished doing an a/c evac and recharge on the wife's '03 Expedition XLT.. The entire climate system works just fine, EXCEPT a/c on the MAX (Recirc) setting. Nice, cool air comes out of the dash vents at idle, but smoothly transitions to the defrost vents when I hit the accelerator. Soon as I take my foot off the gas, it transitions back to dash vents. I traced the vac line from the intake manifold, replaced a splice that seemed to have "collapsed" at the check valve / tee, but no joy on the problem. The end of that line is the vacuum reservoir tank next to the battery. Could I have a cracked line under there that ONLY affects the recirc door vac circuit, or is it more like somewhere in the cabin under the dash (closer to the door mechanism)? Thanks in advance!

 

[Bain64]

Yes, vacuum leak will do this as you note. Is it EATC (electronic automatic temperature control)?
There appears to be a vacuum control motor for behind the instrument panel as well. I tried finding a vacuum diagram but not coming up with anything right away...

 

[1955moose]

If it only reverts to defrost at that setting only, sounds like a hose. If its Eatc, which when these symptoms happen almost always are, run a self diagnostic, to see if any codes pop up. With vacuum lines, sometimes like intake leaks, run new ones, a roll of hose is only about $30.00 or so. That's what I did on customers cars, it resolves the problem, and you don't have to worry about future leaks.

Sent from my N9131 using Tapatalk

 

[dlyoung1]

Thanks for the input. No, we are not EATC, so I'm looking for a vac leak. @Bain64, man would a map of the vac system be wonderful to have!

So, with the problem only in recirc mode, is there a vac line that branches off of the line to the reservoir bottle that comes through the firewall to the recirc door? Could it possibly be a leak in the dash off of the vacuum motor switch (behind the mode select panel)?

 

[John Christopher]

Just finished doing an a/c evac and recharge on the wife's '03 Expedition XLT.. The entire climate system works just fine, EXCEPT a/c on the MAX (Recirc) setting. Nice, cool air comes out of the dash vents at idle, but smoothly transitions to the defrost vents when I hit the accelerator. Soon as I take my foot off the gas, it transitions back to dash vents. I traced the vac line from the intake manifold, replaced a splice that seemed to have "collapsed" at the check valve / tee, but no joy on the problem. The end of that line is the vacuum reservoir tank next to the battery. Could I have a cracked line under there that ONLY affects the recirc door vac circuit, or is it more like somewhere in the cabin under the dash (closer to the door mechanism)? Thanks in advance!

I had a similar problem and a vacuum hose had come loose under the hood. You may have knocked one off when working on the system. Check this out you may solve the problem.

 

[BRIANGEE]

I'm up against the exact same problem right now. Unfortunately my wife has the expy right now so I can't continue to work on it.

I've uploaded the Ford factory service section regarding the climate controls - there is a generic vacuum diagram in there. There are some diagnostic procedures in there as well so hopefully you will find some benefit in it.

http://www.filedropper.com/climatecontrol


Might want to check this video out too in case it pertains to you:

 

[Stuart Johnson]

Had the same problem it was the line behind the battery tray to boost can....no issues sense. Have to remove tray to get to it though.

 

[BRIANGEE]

Mine ended up being my bandaid coming apart from a year ago. I ended up purchasing a couple of different diameters of vacuum hose and replacing some dry rotted lines and all is good.

 

[plumcolr]

If you have 4wd / awd, put it in awd. If that fixes the problem you have a leak in the vac hoses that go to the wheel hub. Mine was at the connection just above the right front wheel.
Could also be one of the wheel hub actuators.

 

[dlyoung1]

Thanks for the input while I've been away!

Looking at the climate control diagram (and thanks for that, @BRIANGEE), in my case it looks like everything is working OK except for the recirc door. Heater control valve is on the same line (other side of a tee) and is functional. So I need to trace the line from that tee to the recirc door actuator motor. Now, if I only knew where to look for that line . . .