A lot of times this problem is mistakenly called a blend door problem. That's not the case here. A blend door does exactly that, blends warm and cold air depending on the temperature selected on the heater controls, that's in another part of the system This part is called "recirc door duct" - or - "Air Inlet Duct" This duct closes outside air when you select Max AC and causes the blower motor to sound louder My Problem ======== What I noticed is that when on Max AC, there is no change in aiflow/blower noise from regular AC. And the blower seems too loud for the amount of air coming out of the vents If you look where the blower motor is in the 3rd gens, its really easy to get to. Its under the passenger side dash. Three 8mm bolts + 1 holding the wiring will let it drop out. Lean in with a light and look up, you'll see a mesh that prevents tissues etc from getting blown up into the vents. Here is the cause =============== Right on top of that mesh you'll likely see the recirc door, fallen out of position, and resting right on top of the blower motor, blocking the duct, and severely restricting air flow Now what? ========= You cannot replace just the door, its in the Max AC Air Inlet Duct The part is about $49 at the dealer, but requires the dash removal and Ford states 6.9 hrs... that's probably a $700 dollar job Here's what I did for now ============== Empty the glove box squeeze the sides, and lower it to the floor You'll see the top of the blower motor housing - its the round part. Above this is the Air Inlet Duct The duct is kind of tent shaped as can be seen in the exploded diagram above, its #16, and the door is hinged at the top point and swings to each side to allow or stop outside air. This Air Inlet Duct is in 2 pieces. Remove these four 8mm bolts with a small ratchet. Then you can split the two pieces with a couple of flat screw drivers. The pieces are not glued so they can be pryed apart easily. When you've got enough room reach in with a couple fingers and pull out the door. This is the door Its much bigger than I thought. Once its out, replace the 4 bolts of the Air Inlet Duct, and put the glove box back up. Bolt the blower motor back up too. After doing this, I now have the air flow on speed 1, that I used to on speed 4. But wait! What about a permanent fix? =================== The downfall to this workaround, is that you always have outside air coming into the system (as you would on regular AC) Here in FL, that can be really hot air, which will not allow the AC to cool as efficiently. The opposite would be true in colder climates, when driving, you'll have cold air coming in behind the glove box and you wife may have to cover her legs with a blanket So after I removed the door, I sealed up the intake outside the truck. 1 - open the hood 2 - remove the passenger side cowl grill (its just snapped in) 3 - Just below the windshield, there is triangular plastic cover that's snapped in but does have some sealant on it. gently pry this off. 4 - Then if you look inside, you'll see a scoop shape on the firewall with a gap at the top. This gap is where the outside air comes in. 5 - I sealed it off with clear packing tape for now as I plan to remove it later when I replace the duct. I dont have time right now to pull the dash so this is just to allow more air so I can feel it on my face. With this door restricting air flow, the AC would not move a hair on my head, but now it does! In the near future, I will replace the Air Inlet Duct assembly For Ford Explorer and Mercury Mountaineer 2002, 2003, 2004 & 2005 the part # is 1L2Z18B259AC, list price is $49.60 This site ----> http://www.denlorstools.com/autoblog/2008/08/2003-ford-explorer-ac-not-cold-enough/ has excellent instructions for doing it without removing the whole dash as Ford would have you believe they do. This guy can replace the part in 45 minutes, so I'll budget a few hrs for me. Hope this helps someones cool down quicker, or at least offers a way to diagnose a similar problem.