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Vacuum Lines Cruise Control

34K views 26 replies 9 participants last post by  coralman 
#1 ·
96 ZJ 5.2L V8
So my cruise control doesn't work and my air only blows out of the defroster... I have found a bunch of threads that point to vacuum lines being the culprit here. However, I was wondering if anyone had some useful pictures of where to start/what to look for?
 
#2 ·
the vacuum line that comes off on mine and causes this same exact issue is located right around the area circled in the pic



it comes straight off of the intake manifold if i remember correctly. ill try to take a close up pic later, this is a random one i found on the internet.

yours could very well have a leak somewhere else but that is one that comes loose whenever i check my trans fluid and i think it is a common vacuum line to come off.

Good luck!

ah sorry this was a pic of a 4.0 which i have. the diagram below seems to have the thing on the opposite side for the 5.2
 
#3 ·
The OP has the 5.2L, not the 4.0L. Here's the vacuum routing diagram for the 1993 5.2L - it shows that the vacuum for the cruise and climate systems comes off the left side of the intake manifold (as you're looking into the engine bay). The 1996 may of course be different, but probably isn't. Just follow the line coming off the PCV valve on the left valve cover, and it should hook up to the manifold right next to where the the cruise/climate vacuum line is.
 

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#15 ·
Rhe problem is the small vac line coming off the t is disconnected and I can't see where the other end is. Also I have a losse electrical connection. It is a two prong plug that comes out neer the far passenger side and goes over the coolant reservioir. I can't see a mate. I would upload pics but I can't seem to do so from mobile Anyone offer solutions.
 
#16 ·
Not sure about the 5.2 but on the 4.0 the small black plastic line to that T goes through the firewall by one of the aluminum AC evaporator tubes as ZeeJay already mentioned. You may have to fish around a little in the foam around the tubes and hopefully it didn't fall all the way in. That line is the feed for the vacuum switch which controls where the air flows from the ducts.

Do you have an under-hood light for the engine compartment? If not that might be the plug to it and look at the below photo of the plug along with my 5th post.

http://www.jeepforum.com/forum/f13/any-guesses-what-goes-1504582/
 
#19 ·
Good point coralman and w/a limited you probably have a coolant level sensor. We just had a discussion about this and if you have a Limited/VIC there's most likely a windshield washer fluid level sensor. Since mine's a Laredo w/o VIC (lucky me, lol) there's no float/sensor in the windshield washer fluid reservoir or the coolant reservoir. Wouldn't doubt I may have a small 2-prong plug laying around the coolant reservoir with nothing it connects to since there's no sensor. ;)
 
#22 ·
Well, I wouldn't mind having a VIC if I knew how to fix it if it started acting up. Sounds like you do coralman if you were able to wire one in yourself. ;)

So the vacuum line is fixed and all is well with the blower motor control. And the loose connection was originally for a coolant level sensor, but the coolant system was upgraded years ago (before i got the car) and the connection is now just a dinosaur. I capped it off. Thanks for all the help.
Glad your problems are figured out/solved. Sometimes I'll run across a rogue connector which must have been for an option I don't have and as long as things are working fine I tend to ignore it. But not a bad idea to figure out what it's for.
 
#21 ·
So the vacuum line is fixed and all is well with the blower motor control. And the loose connection was originally for a coolant level sensor, but the coolant system was upgraded years ago (before i got the car) and the connection is now just a dinosaur. I capped it off. Thanks for all the help.
 
#23 ·
Hi guys I'v got a similar problem with my 2004 4.0 TJ, on the left side there is a vacuum line that is loose, it is supposed to go to a small box on the left side (will post a picture later) but think the last owner just closed both ends, now cruise-control isn't working, you think this might be the problem? A/C works fine.
 
#24 ·
This is my first Jeep (95 Grand Cherokee Orvis edition, 5.2 V8) and it has a few projects ahead for me. However this thread discused both vacum and empty electric connections so I thought Id ask...........

There is a large black hose coming directly off of the passenger side of the manifold that is plugged. Im sure it needs to go someplace and I have a number of issues it might effect.

Also there is a large plug coming out of the wire harnes along the firewall on the passenger side as well.

Tried to show both in the attached photos. Any thoughts on where these need to go?

Thanks
 

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#25 ·
Revisted this thread, as I often do others when I just can't stand to watch one more wonder drug commercial on TV. I suppose it will eventually get to the point one pill will do it all, low chloesterol, lower blood pressure, toe nail cure, keep your junk up, depression supplements to your depression meds, depression meds, and the damn commercial will be 4 hours long. Geesh. Anyways, I'm thinking of modifying a brake line or some metal tube to take the place of the vac line through the firewall. In the next few weeks the climate control housing is coming out anyway to be reworked.Maybe a sleeve of some sorts. Of course I may just say say to heck with it cause the side effects list is too long.
 
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