So I have been dealing with an intermittent issue for a while now (read over a year!)...
I have brought the issue up at two different dealerships but of course the problem never occurred when I brought the jeep in....
Therefore the supposed barrage of tests never identified a problem.

That was until a couple of weeks ago when I picked my wife up from work...
Basically what happens is the venting seems to lose its brains!
The blower is working (should since one dealership assumed that was the issue and replaced it and then there was the recall not long ago which replaced it again!) and I can hear the air moving and the heat works because what little air escapes the vents is hot BUT that is the issue... When set on 4 there is the equivalent amount of air as if it was set on 1.... It sounds like it is on four as far as the noise in the dash is concerned!

When it was malfunctioning the tech even said it was likely a vacuum hose issue but of course a few days later when I brought it in for service they couldn't replicate the issue and only ended up replacing the instrument assembly for setting the fan speed, temp, etc... And this was AFTER I actually brought it in with the problem happening!!!!!

I am almost at the end of what little rope I have left...
Hopefully there are others that have experienced similar issues or that can lend some expertise...

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06 Renny - Dark Khaki
Full skids, rockrails, lightbar, sunroof
245/70/16 Firestone Destination ATs (yeah baby!)

- KJ eXpeditionary Group : Founding Member
- Southern Ontario (S.O.) L.O.S.T
- CarDomain #2347285

Not to sound incredibly arrogant here but the vents weren't blocked by chance were they? I mean the outside vents which suck the air in.

Have you checked the internal venting for possible fillups?

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L.O.S.T forever!
Silver 2002 Skoda Fabia TDI, 235,000km
Former car: Jeep KJ 2003 CRD

DIESEL - saving millions of liters of petrol every day!

did you or they check to see if the blower motor restrictor is going bad? It is an issue on a lot of our rigs. I replaced mine this summer, its pretty typical for them to cause havoc.

it seems that you have the typical symptoms. blower will work fine and say settings 1 and 2, but not work on3 or 4. When the restrictor goes completely, no settings will work.

The restrictor is a little credit card shaped unit which is located behind the glove compatment. It is held in place with 2 screws. It is very simple to replace and the piece itself is pretty cheap. may be worth trying if the issue is really driving you crazy.

here is a thread on it from another forum, and explains how to replace it
http://www.jeepkj.com/forum/showthread.php?t=26012

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L.O.S.T. #225019
2003 Sport 4x4
Patriot Blue w/ trail rash
Flex-Zilla 4" Lift
TrailRash hi-lift mounts
Other stuff you wish you had

The dealership has been all over the rig several times... most recently only a few weeks ago... And they said nothing was wrong... Of course this is an intermittent issue so naturally there was nothing wrong when I brought it in....

If it was constantly not working then I could definitely see that as a cause...

_________________
06 Renny - Dark Khaki
Full skids, rockrails, lightbar, sunroof
245/70/16 Firestone Destination ATs (yeah baby!)

- KJ eXpeditionary Group : Founding Member
- Southern Ontario (S.O.) L.O.S.T
- CarDomain #2347285

it was intermittent for me at first too...just a thought though......good luck!! seems like a tricky one

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L.O.S.T. #225019
2003 Sport 4x4
Patriot Blue w/ trail rash
Flex-Zilla 4" Lift
TrailRash hi-lift mounts
Other stuff you wish you had

Thanks for the suggestion...
I don't have the time to tear it down myself but I will most certainly ask the tech @ my dealership to look into it! This definitely sounds promising...

_________________
06 Renny - Dark Khaki
Full skids, rockrails, lightbar, sunroof
245/70/16 Firestone Destination ATs (yeah baby!)

- KJ eXpeditionary Group : Founding Member
- Southern Ontario (S.O.) L.O.S.T
- CarDomain #2347285

It's not a restrictor - it's a resistor - and if it's bad, then blower setting 4 works (straight 12 volts) but the other setting don't - because the resisor plugs in to lower the blower fan speed.

That doesn't sound like the problem.

The rest of the heater consists of the hoses that are open/closed with vacuum switches - i.e. you have a vacuum line that moves a plate that closes or opens a hose - that vents the air flow from feet - to dash to windshield - it sounds like one of the vacuum lines is pinched or leaking - not allowing a vent to open or close. Not sure of a good way to check. On my Camaro - I pulled out lower dash board pieces and traced them - not sure I want to do that with the Liberty. (sounds like the dealer doesn't want to either)

Another possibility could be leaves or something being pulled into the outside vent and clogging lines - that's real common on vehicles parked under trees.

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2005 CRD
stuff
Skeptic quod gratis asseritur, gratis negatur

The main blend door is vacuum controled and this has to be the problem. As ATXJK suggested: trace the lines from the HVAC control head to the actual HVAC unit and look for pinched or broken lines.

The problem will be very hard to spot but this is certainly a vacuum issue.

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02 Liberty Limited
Silver Outside & Taupe Inside
Heated Seats, Sunroof & Infinity speakers
USA Spec I-Pod adaptor, Mopar Sub, Garmin GPS
Tow Package, Select-Trac
Rock Rails, Tow Hooks

tomato, tomAto....restrictor, resistor. they actually are different though.

but mine didn't work on 3 or 4 at first, then 2 went out, then finally nothing worked. not sure why, don't really care as long as its fixed.

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L.O.S.T. #225019
2003 Sport 4x4
Patriot Blue w/ trail rash
Flex-Zilla 4" Lift
TrailRash hi-lift mounts
Other stuff you wish you had

If the blower is blowing, and you can feel heat but very little coming out, but with high blower noise, I would suspect the blend door is not working correctly. I believe there is an electronic motor which controls the blend door operation. Maybe that is the culprit. These pics are all from a DC FSM, I can not explain the missing part numbers/pics.