I've been trying to track down this issue for a while now. I've narrowed it down to the actuators appear to be working and the lines all seem to have vacuum. I suspect that the previous owner replaced the vacuum lines to the actuator at one point. I've noticed that when I put it on defrost nothing comes out of the dash and no matter what the floor boards blow all the time. So now I'm thinking the when he/she replaced them they had all the lines hooked up backwards and I'm just wondering if anyone has a diagram or any pictures of the hoses that they could share.

 

Even with the vents on defrost, you will still get some airflow out the floor vents. (should be around 10% or so.) If you get full flow down there, then yeah, something ain't quite right. For those diagrams though, I suspect you are going to need the factory service manual.

 

I don't get any air through defrost... None at all actually. No matter what the floor vents blow. I can physically move the actuator to close the floor vents and open the defroster vents but it won't do that if I select defrost using the HVAC Controls. The 2 lines on that actuator are red and brown if I recall. Yeah, I've been trying to thumb through the FSM since last night.

 

If vacuum fails, the vents should default to defrost......

 

I think it might be a bigger issue. I can move the actuator and hear the door for the floor/defroster vents move and close... but no air comes out of the defroster vents. I get mild air out of the dash vents and most of it blows through the floor. This is what confuses me the most. :/

 

Did the door break loose from the axle????

 

I thought about that, but you can hear a thunk when you move the actuator by hand. When I do this the air stops blowing through the floor vents but still doesn't blow through the defroster vents.

You know... on second thought.. They're complaining about the vents not working but they won't bring it over for me to fix... I'm just going to call this not my problem until it's in my hands again. :/

 

Wonder if there is a mouse nest or some such in there, blocking airflow.

I had one truck that has sat for five years, that the vents weren't very cooperative. Turns out there was a HORNETS NEST in there....... Glad I wasn't around when whoever first tried to move it got in there. That had to be exciting........ We tossed a bug-bomb into the truck, and let it sit for a couple days before we would even touch it.

 

Might be. I know that the guys we bought it from used it for junk yard runs... so there's no telling what it did before that.

 

Time to resurrect this thread. I've got the Durango back at the house until Wednesday. So here is what I've noticed. Floor vents work as intended. There is little to no air coming out of the dash vents and absolutely zero air coming from the defroster vents. Both vacuum actuators move with dash controls changed. Tomorrow I'm going to bring some tools home to see if I can figure this out.

Edit: I suspect that the "heater vent door actuator" is either disconnected from the lever or the leaver broke off. When I reach u pin there the rod feels loose and I can feel it scraping on what seems like the side of the heater box.