Another vacuum line/heaterissue

Friends, I have a 98 with 4.0L, automatic trans. I have studied the air-only-comes-out-of-the-defrost threads over and over. I have checked my vacuum lines under the hood and now my dashboard is disemboweled all over my garage! The climate control is not working, cruise control is fine, and there are no leaks under the hood. I took the lines off of the climate control unit and there is clearly no vac getting to it. Questions:

1. Where does the vac line for the climate control go through the firewall?

2. Where does that line go from there?

3. What do I say to my wife who is threatening to take it to the dealer before I get violent with it?

Grig

it does go through the fire wall on the passanger side, and from what i have found that is usually where the break is, the bend is pretty tight. I just took some hose with the same id as the vac lines od and slid both ends into it, worked great. I will try to get some pics taken for you in a bit.

heres your pics.

Nighthawk,

Thanks for the reply. The pics are very helpful. But... It has become clear that my XJ vacuum lines are connected differently than yours. I think it may have been modified by the previous owner. I am going to take you pics and see if I am replicate your system in mine. Although it is conceivable that there are variations in different years.

Grig

Nighthawk, I have no plumbing entering the firewall where your pics see one. I have one small hose entering the firewall about 10" straight below the two heater hoses. That small hose comes out of the big wire harness up above and goes directly to this entry point with no "T" junction. This small hose has has no vacuum. I may try plugging a vacuum line into it and see what it does. Does any one know for sure what this line is that goes into the firewall 10" down from the heater hoses?

G , post some pics of what you do have, and some pics from a bit further back, if you have a vacume line running somewhere under the hood, you can always take and put a t in it, and run it to your heater.

But, then you still have an open vacume line somewhere else, and from my findings, this is not good. You really want to have all your vacume stuff connected. These vacume lines are real hard plastic, and get dry rot and stuff with age. This is kinda a mopar thing, has been a problem for years, and i delt with it alot in my jeep and my 72 dodge demon.

Just start looking for small plastic hoses that are broken, and look at every thing that goes through the firewall. Make sure that the rubber damnit that goes around all the wires and hoses is still good and you dont have any hoses or wires gettin cut from the sheet metal.

Alot of the vacume hoses make a very sharp bend, and that old plastic gets brittle, just changing your heater from one point to anouther can make them break. I used more hose than needed, but eliminated that sharp bend.

anouther thing i found is, when changing from defrost to floor or vents, turn your fan all the way down, then make your selection, and after it starts moving the air, then turn your fan back up. The ammount of pressure that the fan creates can make it to where the week vacume setup cant move the flap doors.

Um, im sure others will disagree with what i have said, but thats just what i have found.

Well the next episode is that I managed to shove a stiff plastic vac line through the firewall hole and was able to catch on the other side with a coat hanger hook (wonderful tool you know!) after taking out only the glove box. The next step is to hook a live vac line and see if that solves the problem. Thanks Nighthawk for the good pics. They are what helped the most. I appreciate your taking the trouble. G

no problem man, just let us know if we can help you with anything else.

Subcribing to thread since my climate controls are starting to go a bit wonky and will be line testing this weekend.