I have a very similiar issue with my 01 limited as well. I really only get good air flow from the left center vent. Air barely trickles out of the driver and passenger side vents, even at HI fan output. Defrost and heat vents produce great airflow. I've been trying to figure out what is causing it and I'm convinced there is some blockage in the air ducts. I'm sure it requries a disassembly of the dash which I do not want to complete. I've been able to improve the air flow little by little by doing the following:

1. If blend door was replaced check the work. Look for tight seals and no cracks where air can escape. Whoever did mine cut out the section of plastic near the glove box but did a terrible job re-securing it. Tons of air flow was being lost so I sealed it up much better.
2.Replaced fan blower resistor and fan blower motor. Figured out the "upgraded" wiring harness had the wires reversed and resulted in the fan spinning in the wrong direction which caused a significant loss in air flow.

As to your question about the possibly missing line/connection in your diagram, I'm not sure what that is. Can you access that connection point without taking apart the dash? Looks like it's almost on the driver's side? Let me know how to visibly inspect that and I will check mine.

 

I have a very similiar issue with my 01 limited as well. I really only get good air flow from the left center vent. Air barely trickles out of the driver and passenger side vents, even at HI fan output. Defrost and heat vents produce great airflow. I've been trying to figure out what is causing it and I'm convinced there is some blockage in the air ducts. I'm sure it requries a disassembly of the dash which I do not want to complete. I've been able to improve the air flow little by little by doing the following:

1. If blend door was replaced check the work. Look for tight seals and no cracks where air can escape. Whoever did mine cut out the section of plastic near the glove box but did a terrible job re-securing it. Tons of air flow was being lost so I sealed it up much better.
2.Replaced fan blower resistor and fan blower motor. Figured out the "upgraded" wiring harness had the wires reversed and resulted in the fan spinning in the wrong direction which caused a significant loss in air flow.

As to your question about the possibly missing line/connection in your diagram, I'm not sure what that is. Can you access that connection point without taking apart the dash? Looks like it's almost on the driver's side? Let me know how to visibly inspect that and I will check mine.

I used a lot of duct tape when i did my blend doors and the previous owner had the blower motor resister done. i checked it and its turning the right way.

about the missing line- if you pop the hood and follow the ac lines back to the firewall (left of motor), youll see the 2 coolant lines as well, below that is the nipple with nothing on it. youll have to really look because its down there pretty far.

the guy that had the jeep previously definitely messed around with the climate control, but didnt by any parts to fix it properly.

 

Oh, and my automatic zone control can be quirky when I start the vehicle as well. Sometimes it will remember it is "on" and the proper fan speed. Other times I have to move the fan control knob for it to recognize it's "on" and it will start moving air.

When you say you get 90% air volume from the center/defrost ducts, are you getting equal airflow from BOTH center vents? Oddly enough my left center vent gets the most airflow, right center just kinda trickles out very much like all of the other dash vents. Odd...

 

When you say you get 90% air volume from the center/defrost ducts, are you getting equal airflow from BOTH center vents? Oddly enough my left center vent gets the most airflow, right center just kinda trickles out very much like all of the other dash vents. Odd...

more from the left, just like yours

 

ooh ooh i know.... lol. It sounds like a cracked vacuum line, happened on my 01 TJ. Not sure where it is on our WJ's as i have not had to do it for mine yet. But on the TJ it was a hard plastic tube about 1/4 diameter and ran along the passenger side of the engine bay closest to the firewall & into where the a/c lines go into the cab. My buddies 94 civic did the same thing as my TJ a/c only blows from the defroster until the line is replaced(i cut it and sleeved it with a rubber hose) and his civic was back in business. The first time it happened i didnt know what it was, & the dealer charged me 103.00 to fix it. 99.00 for the service call & 2.00+tax for the hose they sleeved mine with. You'll know it when you see it however, as it is a hard line & smaller than the rest of the vacuum lines in the engine compartment.

 

If it is cold outside and I set the heat or defrost to high not much haooens until the engine warms up some. Most cars would blow cold air but I believe our Jeeps wait until it can blow warm; could this be some of what you notice?

 

I recently had a similar problem with not much air coming out of the middle vents or any vents recently. Fan was blowing fine so that wasn't the problem. I just let it go until yesterday when I had the middle console taken apart to replace some bulbs in my heater control unit. While I was in there I took a look around and found that the where the vents mated up with the ducts behind the dash there was a piece of foam rubber that was supposed to seal the connection. Well there was about a half inch gap all around the connect so most of my air flowing through the vents was going out of these gaps and behind the dash. The air from the fan was taking the path of least resistance and almost all of it was going out this gap.

What I did to fix it was spray some Great Stuff around the edges to fill the gap. This is the stuff that comes in a can that you can get from Home Depot that is used to fill gaps in your house or whatever. It's really messy but as it dries it expands and hardens into a solid foam creating basically an air tight seal. I also found that once it dried and hardened it wasn't too bad to go back and pick off the pieces that went were I didn't want it to from the mess I made. After it dried I put it all back together and now I have decent air flowing from my vents.

Why they didn't do something like this from the factory rather then a crappy piece of foam rubber that probably never sealed when it was new I have no idea.

 

briandor, what is the middle console piece that you had apart? The piece that contains the cd player + temp/fan controls? How hard is it to check that vent seal?

 

Yes. I had the radio, temp/fan control, and bottom piece with the ash tray and outlets removed. Probably didn't need to remove the radio but I wanted to see if it gave me any additional access. Checking it is pretty easy. You'll see the vents right in front of you when you open it up. Just check the gap where the vent piece meets the bigger unit behind it. There will be a piece of foam rubber that is supposed to seal that gap but it seems that the plastic pulls away from it and I had about a half inch gap all the way around it. It wasn't hard to seal with the great stuff it was just messy. There may be a better option but that is what I already had.

Also if you change the vent settings on your controls you will see the door move right behind those vents. You will want to be careful not to get anything down in there that would prevent that door from sealing too. It's also covered in foam rubber so it's already not doing the best job sealing.

 

im pretty sure the circled area of your picture is the hvac drain. there are no hoses that go there

 

Pardon me for asking but how did you remove the radio, temp/fan control, and the bottom piece with the ash tray/outlets? Are there any step by step guides available? I'd love to take that stuff off and inspect the vents + seals as I suspect that is exactly the problem I have with air flow. Thanks for the help!

 

I don't know if there are any step by step guides but it's pretty straight forward. The trim around the radio and the bottom ash tray piece are just clipped in. You can just use a flat screwdriver along the edge to pry them off. Just be careful not to mark the trim and you'll be fine. It will just pop right out and it shouldn't take too much force. The piece around the radio came out easiest for me. You do need to take the radio trim and ash tray piece off to get to the screws that hold the temp/fan control in place.

 

not tryin to hijack...but,

I also have a 2001 with the automatic climate control. My problem is this, even when I have the right knob turned all the way to the OFF position, I still hear things opening and closing behind my dash. Is this common? I've never had a heat and AC unit make so much noise in the Off position.

 

RepomanNC I hear that from time to time as well along with some other odd noises inside the dash. Sometimes I hear the sound of running water as if I'm near a small stream.... sounds like it's coming from the heater core area behind the glovebox/passenger airbag.

I think when you turn the system off it closes the re-circulation door. Does your automatic zone control module give you any fault codes? There's a diagnostic process that involves pressing certain buttons... I forget the combination on buttons but look it up.

 

"hear the sound of running water as if I'm near a small stream.... sounds like it's coming from the heater core area behind the glovebox/passenger airbag."

You should probably bleed your cooling system to remove air