Not sure if this has been answered before but I could not find anything. I have a 02 2500 5.9 diesel and I don't seem to be able to get any volume out of the dash vents. This seems to be more on AC so I guess it could be Icing up maybe? It never really seems overly forcefull even when first turned on. I have checked the vacuum hose on the firewall and I can hear the doors closing in the heater compartment so not sure what the trouble is. How much trouble to get apart?

Might be the evaporator is plugged up with road dust. http://t1.gstatic.com/images?q=tbn:ANd9GcS0dhysP3h9h849z4j-OkNE_XjZBolTW1r0Jy05EOszER6ptWZ3 Its a weakend project to remove the HVAC case...

http-~~-//www.youtube.com/watch?v=ghDbhJDBvkc

You have got to be kidding! Is there no way to clean that thing without disassembling the whole truck? What happened to the old days when it was a plastic cover under the dash? That means I have to evac the AC and then charge it up again and that seldom ever goes right.

Try dropping the blower motor in the passenger's foot well. You may find the blower plugged. Despite "hearing the vacume door" it may be that the vacume pull is broke. The default setting is defrost. If the air only comes out the defrost, possibly this vacume diaphram is failed.

I will have to look it over I guess, I know there is a spray that can be bought that is supposed to disolve dust pet hair and all that stuff from your heater core or condensor but I am not sure that if it is possible to get at it to spray?

Part placement...

I have not tried it on the truck but my Cirrus is constructed similarly. I was able to get my hand in through the blower hole & clean out by hand (YUCK!!) mouse nest from the face of the AC unit, also got the shop vac end in with difficulty with the hose in an upside down J config sucked out the YUCK I'd freed up with fingers. The blower comes out with 3 screws... arkward for me with a bum hand but ordinarily no big deal. I've also found the blower cage a spinning Merry-Go-Round of lint which sure did not flow well. IF this proves to be the problem... get some SS steel wool (used pot scrubber) and stuff behind the hood hinges in the engine bay. It keeps mice out of the cowel area & thus out of the heater but still allows rain to drain out. (I did mine in 2002 & still going strong... I still get mice under the hood but none in the cab.)Test as follows: blower blows at all? Where? Defrost = diverter door NO, blower / duct obstructedTemp wrong / won't keep up = blend door servo/coupler The blend door is a PITA but can be done from the passenger's foot well. I can give more info if that proves to be the case.Let us know...

Have you had any luck on your air coming from your blower yet? If not there is a couple of options that you can use! I have used both and they work pretty good, without having to totally disassemble the dash! One is you remove the blower motor, and spray some aluminum brightener, which will dissolve any trash and immediately flush the unit with water! Or go to your local part store and see if they have A/C Pro evaporator odor eliminator. Autozone and Oreilly's both can get this, its really simple to use, pop the hood locate evaporator drain, insert clear hose into drain, spray at least 15 seconds, wait 15 mins and you will see trash foaming out drain, then turn your blower on low and let run for 10 mins! This stuff leaves a pleasant smell from the vents for a while, and it removes mold and bacteria which grows on the core! It normally runs 12-15 bucks a can, and it is well worth the price! If any of y'all can't find it let me know, an I'll ship you a can!