Hi everyone,

1999 xj classic. I was driving in the rain and tried to defog my windscreen but felt pretty much no air coming out of the vents. Does anyone know how to get under the vents to clear it out or see what is wrong? Or could it be something more than a blockage?

Any help would be much appreciated. Thanks!

 

sounds like your blend door stuck. Does the air blow out anywhere else? Where does it blow when set to blow on the windshield?

 

hey, yeah it blows out everywhere else apart from the windscreen. When I change it to defrost it makes a lot of noise but not really any air, just a little from the front vents. Is the blend door something I can reach if I remove the stereo?

Thanks for the reply.

 

I don't know about the newer XJs but on my 93, if you look up under dash on the passenger side, you can see and access the door there.

 

just so I understand, does the blend door direct the air from the footwells to the front facing vents and then to the de-fogger when you switch between each setting on the ****?

 

you know what, I got mixed up, the blend door changes the cold to hot air. Lol. But I think there is another door/actuator the moves the air from the foot wells, to front vents to defrost. wait for someone else to chime in, they'll know.

 

The vents are vaccum actuated, and typically what goes wrong is there is a crack in the vaccum line causing air to only blow out the defrost, but in your case, it's the opposite, so Im not sure.

 

This is a jeep tj but the interior is very similiar to yours, maybe this will help. http://www.wranglerforum.com/f210/ac...nts-15844.html

Also, go ahead and check the vacuum line and make sure there are no cracks or vacuum leaks, here's a diagram.

 

When you tried to defog the windshield did you have the mode selector in Defrost or Mix? (See diagram below)


If you used Defrost, try Mix and see if air flows from the floor outlets and the windshield outlets.


Note in the diagram that the defrost actuator has vacuum applied to it in all mode selections except Defrost and Mix. In Mix half the Defrost actuator is vacuum powered and the other half is not.


If there is no airflow from the Defrost outlets when in MIX the bell crank link on the Defrost door may be broken.


Try Mix and tell us what happens. If there is no airflow there is a way to visually check to see if the Defrost actuator is working in Defrost and/or Mix, or if the bell crank is broken.



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Okay thanks for all the great responses. I will check it out and let you know.

 

Hey everyone,

So I ran the air with the mix of feet and windshield and the feet blows perfectly. So i'm guessing its the defrost door. It sounds like when I put it on just defog the door is blown closed and thats what the blockage is.

Does anyone know if its a fix that I could do myself? I saw on youtube a guy who was able to plastic cement back together the arm, as it had broken at a accessible point. But I know that will eventually break again. Any tips?

Thanks.

 

Likely a broken defrost door arm especially if, when you turn it on in the 3 or 4 position you hear a distinct "FAP!" That's the defrost door blowing shut from the air pressure because the arm is broken and no longer able to hold that door open. Very common problem.

I'd love someone to make some new arms out of aluminum or something instead of plastic destined to break again because I have the same problem. Unless you have very tiny hands, you'll have to pull your dash to replace it.