stuck in defrost

[justintimemoto]

The other week i was driving and i went to change to the floor vents and it would only come out of defrost, no matter what setting i push... The on the fly 4wd dont work unlesss the hubs are locked in. but all the vent stuff used to work no matter what where do i start thanks.

 

[Atsah]

Vaccum leak somewhere in the system.. There is a TSB on it..


Some 1999-2006 F-Super Duty and 2000-2005 Excursion vehicles built before 6/27/2005 and 1999-2006 F650/750 vehicles, all vehicles equipped with the 7.3L or 6.0L diesel engine, may exhibit a vacuum pump that is inoperative or running continuously. If the pump is inoperative, the climate control system will default to defrost mode and the 4x4 system may also be affected.

 

[dmd]

Vaccum leak somewhere in the system..

Or the vacuum pump. If it is a leak it may be a hub or the connection to
a hub.

 

[vcassens]

Try unhooking your vacuum hubs and plugging your lines up and see if that fixes it that is what was wrong with my 04

 

[Mdub707]

Try this Justin:

http://www.youtube.com/watch?v=MoI-BbisYEs

Mine do the same thing... just haven't had the time to check it out...

 

[doubledee715]

dealing with this. haven't dug into it, was told the leak could be behind the dash in a worst case scenario. A member told me that's where his was. not what I wanted to hear. It is not my vacuum pump. Will check connections to hub, it's cold out so I plan on dealing with it when I rebuild this summer.

 

[doubledee715]

thanks for that video. check vacuum lines, if those are good, get tool to test if hubs hold vacuum. if hubs, he's not sure but he thinks it's an o-ring. Is he right? is it an oring if it is the hubs leaking vacuum? Thanks again good info I needed.

 

[doubledee715]

how come his dash vents worked before he turned it to 4hi or 4lo, then it started coming through the defrost. Mine comes through the defrost on any air setting.

 

[Atsah]

how come his dash vents worked before he turned it to 4hi or 4lo, then it started coming through the defrost. Mine comes through the defrost on any air setting.

If it's just a leak it will do this.. Mine does this if my fan speed is on high and I put it in 4x4 HI.. If I turn the speed down it will engage the 4x4 and then I turn the fan speed up and it works okay.. He has a small leak somehwere in the system.. His pump seems to be working..

 

[doubledee715]

Thanks atsah, my vacuum pump is in good working order also. I haven't looked over all the lines yet I just confirmed it wasn't the pump. now i have a better idea of what lines to look at. blah I hope it isn't the one under the dash.

 

[dmd]

how come his dash vents worked before he turned it to 4hi or 4lo, then it started coming through the defrost. Mine comes through the defrost on any air setting.

If the hubs are leaking the vents will work fine until 4x4 is set. Yours probably is not the hubs.

 

[doubledee715]

If the hubs are leaking the vents will work fine until 4x4 is set. Yours probably is not the hubs.

Thanks for that. Now I will be glad if it is the line under the dash.

 

[Arisley]

Look under the glove box. There is a line there with a tee in it. Your wife or kids toe can hook it and unplug it real easy.

 

[vcassens]

If the hubs are leaking the vents will work fine until 4x4 is set. Yours probably is not the hubs.

Not always true my 04 just wold not work it didn't matter if it was in 4x4 or not and it was my hubs and I have seen a lot of these trucks have the same problem.

 

[justintimemoto]

k thanks guys, now just got to wait for it to warm up outside.

 

[justintimemoto]

fixed it thank the lord for smoke machines. it had a bad hub seal and vacuum pump

 

[Atsah]

fixed it thank the lord for smoke machines. it had a bad hub seal and vacuum pump

Sounds about right.. Glad you got it fixed..

 

[doubledee715]

if hubs, he's not sure but he thinks it's an o-ring. Is he right? is it an oring if it is the hubs leaking vacuum? Thanks again good info I needed.

was it an oring like the guy in the video said he thought it would be if it was the hub? thanks

 

[Zmann]

when the ESOF 4x4is selected the vacuum pulse is only a short duration then stops ,, if your HVAC isn't working properly all the time do to a vacuum leak then you also have a faulty ESOF actuator at the pass fender near the vac pump ,, it isn't sealing off the vacuum

 

[doubledee715]

Can someone confirm if I'm missing something that is supposed to be attached to this white plastic piece on the vacuum pump? Or normal?