My AC only blew cold air on the fresh air setting and when I put it into the recirculation mode very little air came out.
I Googled the problem and came up with the intense solution on another KJ forum: http://www.jeepkj.com/forum/f196/ac-rec ... ard-51738/

Not wanting to rip out the dash or the glove box, I came up with a easy solution.
First, open the glove box, release the two clip hooks on both sides of the glove box, let it swing down, the left one is shown below.

Next get a good light and look at dust and fuzz clogging the inlet screen located on the top right side of the area behind the glove box as shown in the photo below.

Get out your Shop Vac and clean off the screen, then if you are not an neat freak who vacuums the carpet 4 times a week, vacuum the floor so the dirt, cotton wood fuzz, soy bean fuzz, grass, and dust does not re-clog the screen.
Now, close the glove box and put away the shop vac, you are done and you did not pay the dealer $800 to do it.

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2006 Pearl Green CRD
Magnaflow 2 1/2" Cat Back
KJ Extra Leg Room Brackets, Carter Lift Pump, V6 Airbox, ORM
Fuel cooler, Oil Separator, Progard 7
Gauges EGT Boost Trans Temp Oil Pres, Michelin LXT AT2 245 70 R16
7,000# Draw Tight hitch, PML EX Deep Trans Pan
Centrifuge, SunCoast, Transgo, RAM TCM, InMotion Stage 2
Wife's 99 TDI VW Beetle

Now that's interesting as I just finished approaching possible clogging from the other end not that I was having problems but my experience with a 1993 D-250 Cummins made me worry a bit. On that vehicle and on up thru at least the early 2nd gen series Dodge trucks the vent on the cowl just in front of the windscreen is rather coarse and does little to keep leaves and other cra@ from getting inside where the design of the AC/heat intake (down on the fender wall passenger side) is such that this "stuff" can get sucked into the HEVAC box. In my case the PO had let something rather solid slid off the passenger seat which cracked a small hole in the HEVAC box thru which I could see a rather surprising amount of vegetable matter. I cut the box open to accommodate a small screw in marine hatch and shoveled out that matter and pulled the cowl and glued some window screen to the bottom; end of problem. My worry was obvious as the 05/06 KJs lack a cabin air intake filter that my wife's Honda has and that filter collects all sorts of stuff.

So I checked the KJ cowl area as follows:
1. open hood
2. remove wiper arm assembly - pop plastic cap; undo nut; using a QUALITY wiper blade/battery post puller undo arm from splined wiper arm post - mine required rather considerable force before popping loose hence I stress avoiding the $5 cheapy pullers
3. gently pry and pull up on each of the 4 plastic cowl retaining pins and remove pin and pin base - IdParts sells these for like $4.50 each but they can be removed and reused if you are careful.
4. work the cowl around the hood so you can get to the passenger side - to do so note that you will likely need to reach up under it and pop the wiper fluid hose loose in 2 places and pull slightly forward on the cowl to disengage the plastic arms that fit under the windscreen before pulling up
5. over on the passenger side you will see a raised AC/heater air intake with, thank you DCJ, a window screen type cover over it. Should stop most all big stuff and the little stuff should wash on past the raised skirt. Mine had very little stuff caught in the screen and no visible debris in the fan that you can see thru the screen. I vacuumed up what debris there was in the area.
6. reverse to reassemble.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs