ziegler.1289

So I have a 99 XJ I just picked up and one if the issues is the common problem of air only blowing out of defrost. I have searched through numerous threads before deciding to start a new one. Some of the details are that I have already checked the vacuum ball behind front bumper and there is no leak, when I pull hose off you can hear the stored pressure escape. I checked all the vacuum lines and none have cracks. The cruise control does work fine and it ties into the vacuum line coming off the vacuum ball so I assume that part is fine. Then the line comes around and runs into a T and goes off through the fire wall to the cab and the other runs over to the intake. NOTE: I believe I have a rare vacuum system for a 99, as I do not have all the LDP (leak detection pump) components. Just letting you know that I don't have all the extra vacuum connections the hose just runs past where that would all be. I have tried to listen after shutting off Jeep under the hood and behind the glovebox, and don't hear any leaks. I don't have a smoke tester either. After looking through many threads I have not seen any real solutions, but that may be because alot of people forget to post a solution once they find it. I have heard from one source online of someone who had this problem and their vacuum ball was no the problem, they replaced the actual HVAC controls in the vehicle. If anyone has had this problem like I do please give me a hand. Thanks!

RTorrez1

Have you check the blend door it self to see if you don't have anything in there keeping it from moving???

ziegler.1289

I do know what your referring to, but I don't really know how to access. Could you give me any advice?

ziegler.1289

bump

freegdr

is there vacum at ac control panel ?

ziegler.1289

As far as I have gone to test this is was simply unplugging the group of lines that run into the back of the panel and I heard a vacuum escaping. Should each individual line have vacuum? If so maybe I should check each one individually. Does anyone know know or have a diagram that shows that vacuum line running through the firewall on the passenger side firewall? I have a "vacuum diagram" but it doesn't show any of the routes behind the dash. I guess my question is why is there only a single line that runs into the firewall but then behind the control panel is a series of hoses running into it? At what point does the single line turn into numerous lines or do the other ones come from elsewhere, and if so where? Thanks in advance.

freegdr

single line runs to control panel then is sent to different diaphragms according to selection made, should be some info he3e that will help....http://www.jeep4x4center.com/knowledge-base/index.htm

ck1

I had the same problem and my cruise worked fine, the ball held vacumm...checked all the lines with a hand vacumm pump/gauge and it turned out to be the line from the cruise to the ball...it had rubbed a small hole right where it goes thru the core support and heads down to the ball..not sure if a 99 is the same set up but worth a look

cameron

ziegler.1289

Ok I wont be able to check for a couple days but if anyone has anything to ad please do. THANKS!!!