2nd Gen Non-Engine/Transmission Another 01 air problem

[stebbyron]

I have searched the forum for air problems and have found cold air no hot and hot no cold and air up or air down but my problem is no air at all. I will have defrost or up and down then it sounds like a door closes and even though the fan is going there is no air coming through the vents. The happens at start up and yesterday while I was driving over a pass in a blizzard. It makes for some fun driving. Any thoughts as to how to fix it? This is on an 01, 2500 Diesel 4X4 with 109,000 miles on it.

 

[georgej]

I'm assuming it's a diesel if so I would check the vacuum line on the passenger side behind the turbo that leads to the firewall. Some have reported the 90* fittng has melted. Also check for vacuum pump operation. If this is a gasser then check the vacuum check valve.



George

 

[BenCole]

I have a problem with my 01, also. The heater works fine, warm or cold air, and the blower motor works. It is stuck on the air exiting at the floor (blows good air velocity). I can't get any air on the defrost, and very, very little out the main middle vents. Have replaced the mechanical controls for AC/Heat, but that didn't change anything. Have checked vacuum line from pump to firewall, and all looks fine, and I can feel the vacuum when I open the line. When I go to AC/recirculate, I hear and see the valve move (getting vacuum) and the door shuts or opens behind the glove box. I will appreciate any guidance. Can't get any defrost or air out the center vents.

 

[stebbyron]

Sounds like the key is sheared on the blend door. Do a search on blend doors and you should find it. Mine is still in the search mode for what is wrong. After trouble shooting mine myself, the dealer service dept. took a shot at it and couldn't find anything wrong with it either. As soon as it acts up again I am taking into the shop and not turning it off until they get to look at it while it isn't working.

 

[BenCole]

Thanks for the reply. Tonight I purchased a hand vacuum tool, with gauge. All my lines check out, hold vacuum, no leaks. I did replace the one way vacuum valve (2 feet from vacuum pump), it was leaking. I haven't had a chance to start it up to see if that was the problem. I don't think it would be that simple. After I finish some other items like the blend door you recommended, I will try that and post again this weekend. By the way, I have a code saying there was no communication with the mechanical instrument cluster (MIC) prior to when I replaced the MIC, last night. I haven't checked that out, either. By the way, once a code is set, do we need to do anything to reset something to remove the code?