I had run a search and found this forum and actually the following thread... with the original intention of researching why my HVAC was stuck mainly on defrost (very little air coming from the other vents). https://www.cherokeeforum.com/f5/hva...ls-help-48898/
Then I read that, and I realized my cruise turns on, but I can't actually set it. I followed the instructions and checked for vacuum leaks on the driver's side of the engine, and sure enough - 2 vacuum holes (nipples? what are those things called?) that weren't plugged. Found one hose, and plugged it up (the one closer to the firewall). However, I'm missing the other hose...? And I have NO CLUE what either of these hoses feed to or what (or what for) hose I'm missing for the one further forward. My best guess is that the previous owner unhooked these hoses for easier installation of the K&N ram air system and neglected to do it right.

It should be known this is my first Jeep, and I JUST got it (I know, I should've had it checked... ugh), so I know nothing about these specific cars, but I'm fairly car-savvy. Included is a picture of the area... Can anyone elaborate on what these are and what's missing? I have other issues to solve with the car, but that's another thread..........

Thanks-
Inn

1999 Grand Cherokee Laredo 4x4

 

Could you maybe get some more pictures of the ones that you plugged? And the ones that are not plugged? I just found the problem on mine related to the defrost blowing all the time. for sure, vacuum related. I isolated mine to the "egg" (vacuum resovoir) and diagnosed a friends the same day. (his was just a bad hose on part of that system.)
From that area in the pictures though, I would say, maybe a vent hose for the valve cover?

ahh, the other one likely goes to the cruise module? It should be cyclindrical, and have a vacuum hose (1/4 inch or so) and a cable attached to it (pretty sure)

 

Hopefully this makes it more clear... what you're looking at is (standing at the driver's side of the truck) the intake manifold on an inline 6.


Could you maybe link me to a picture or take a picture of this egg thing youre talking about? I'm not used to the jeep jargon yet =\ And I'm pretty sure I identified the cruise control module underhood, looks familiar to my Miata's.

 

...Seriously? Nobody knows what hose is supposed to be here?

Please, I live in Florida and its summer and I REALLY need A/C coming out of the vents instead of the defrost.. >.<

 

I can't tell you which hose is supposed to be there, but I can tell you how to take care of the problem. Your AC controls opperate by vacuum. There is at least one very small line coming from the firewall to a vacuum source. Also, the cruise control servo under the hood will have a vacuum line more than likely on the same source. Just make sure that that source is hooked to the intake manifold and that it also includes the vacuum reservoir (the ball) behind the front bumper. Then it should work.

 

Okay so I should be looking for a connection near the bumper. The hose I have hooked up right now (to the rear of the two vacuum inlets on the manifold) is coming from the firewall, its the exact length and the bend is exactly where it should be, fits perfectly. Just need to figure out what the vacuum inlet IN FRONT of the vacuum connection directly below the throttle body goes to - I'll fish around near the bumper for the vacuum reservoir and an unhooked hose/connection... Don't know what the reservoir looks like though (you said a ball so I'll assume it looks like that.. any other details as to exactly where or how high/low it is would be helpful).

It seems like hooking up ONE of those two hoses to the manifold would've fixed one of the problems... it hasn't. ...?!

Anyway, thanks for the reply, I've got something to go on now at least.

 

If you can locate the "egg" (inside of the front passenger side bumper, black.) The larger hose will be the supply, going all the way back to the driver's side. The smaller should be the a/c one. if all else fails, turn it on, have someone in the jeep, and suck/blow on each one. it will likely tell you something! Good luck bro.

 

Innsomniac, how's it goin with your AC. I just got a 96 sport with the exact same symptoms. Cold air out of the defrost only, and cruise will not set. Mine has been wrecked or hit a deer or something on the front passenger side by the previous owner. The front bumper is a little bit pushed in so I'm thinkin that egg/ball thing could be your and/or my problem. I'll take a look at mine later today.

 

I looked and no ball/egg. But i did find the vaccum line along the passenger fender that t's into the cruise control thing then forward to where I think the ball is supposed to be. Right under or behind the headlight is where the line stops. Looks like it was cut or just pulled off. However, I cant find any other line that would be hooked to the ball.Is ther only supposed to be one line hooked to the ball?
Dont mean to hijack your thread, just thought maybe we could help eachother out.

 

If it just stops, then you probably have no vacuum. You need to get a reservoir and put it on that line. They you will probably have your controls back.

 

Yeah I had the same problem, sheep. Saw no ball/egg reservoir. Might have been looking too low, was looking from underneath. I'll have to look around the fender for any lines and split like what you found... I didn't even see a hose going across the front bumper to the driver's side =\

Probably need to get myself another res and the hoses for it, too...

Anybody with a ~99 (WJ, right?) have any pictures of some of these various junction points for reference by chance?

 

Ok, I was in a big hurry but i went to the jy and looked for some ball/eggs. I found a 92 XJ that had a long oval (egg) canister with only one hose going to it. The other one I found was a 96 GRAND cherokee. It had a perfect round ball canister on it. Not sure which one I am supposed to have. Can anyone tell me? I got both of them for $25 but some of the mounting tabs are broken. Innsomniac, you can gladly have the other one if its what you need. You can probly find one there cheaper and quicker than shipping to AZ. Just thot i'd let you know that both of them just have one inlet/outlet and the hose just pushes onto the ball/egg. Maybe yours just came unhooked. If you take the passenger endcap off the bumper, its right there.

 

OK put the bigger "egg" canister on mine and that did it! Now my controls switch from defrost to ac, to heat etc. and my cruise works, and my check engine lite went off. Awesome! Thanks for everyone's help. Hope this helps you innsomniac.

 

=\ Glad you got yours fixed... underneath my battery/batt bracket, it LOOKS like a cruise control module... so it seems like my setup is different than what was described here. There's a hose running up the passenger fender like mentioned, but it goes directly to what I THINK is the cruise module under the battery (horrible location, cant see or reach much of anything on it without having to remove the battery and bracket. -.- And I still don't see any other hoses going from that to ANYwhere, not to a vacuum res ball, and not across the front to the drivers' side. Perhaps I should post pictures.... I really wish someone with this model year would help me out with pictures of whats SUPPOSED to be there, and where "there" is.... pleeeeeeeease? lol

Good to hear you got yours goin tho, sheep. I'll probably have to hit up a jy too.

In the meantime... I've got a shop manual, and have been looking best I could to get some ideas of the workings and get some visuals of what I need or what I should have. But I had an idea -

This is an IMPORTANT question if this idea is going to work as a temporary fix: Is the control switch connected to a flap that directs air down the correct duct? If so, I'm prepared to rig the flap to be "stuck" on the front vents for the time being.. I have to make a long trip (6 hrs both ways) friday night and I'd like to rig it before then since repair doesn't seem feasible in that time frame. If anyone can tell me where that flap is, if it exists, I'll do that for now and be greatly in your debt.

 

Remove the battery. Take out the battery tray. The bottom section of the battery tray is actually a vacuum reservoir. If the hose that leads to it is disconnected, you have a serious vacuum leak. It need to be plugged into the reservoir.