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-   -   Where does this vacuum line go? (http://www.wranglerforum.com/f210/where-does-this-vacuum-line-go-252088.html)

biggus35 06-27-2013 12:11 PM

Where does this vacuum line go?
 
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Trying to identify the last gremlin in my AC system. I think the vacuum hose going through the firewall in this picture might be loose. I have looked for it under the dash but cannot find it. Can someone tell me where to look?

I hope I'm not going to have to take the entire dashboard off to find this hose?

P.S. - I'm talking about the small, thin, black hose going between the aluminum and big black hoses.

OhSixTJ 06-27-2013 12:30 PM

You should be ably to see it if you take your glove box out and use a flashlight. This is if you're wondering where it goes once its inside.

biggus35 06-27-2013 12:43 PM

Quote:

Originally Posted by OhSixTJ (Post 3904789)
You should be ably to see it if you take your glove box out and use a flashlight. This is if you're wondering where it goes once its inside.

Yes, I'm trying to find out where it goes inside the cab under the dash. Previous owner left a rat's nest of wires under the dash with an after market radio install and a satellite radio receiver and a light bar. I've disentangled most of the wires and removed what I could but cannot find the vacuum line. I'm thinking it was disconnected when they pulled all these new wires.

If someone knows where it connects under the dash please lest me know. I think it might be easier to find it if I know where it's supposed to be.

Thanks

Gary2 06-27-2013 12:44 PM

I think you will find a Tee near it . One end goes to the vacuum canister under the battery and the one in the picture goes to the mode switch on the HVAC controls. It originates on the dr side of the intake manifold

biggus35 06-27-2013 12:56 PM

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Here is a pic of the control module from inside the dash. I do not see a vacuum line on it anywhere. I do not see a place for a vacuum line to attach anywhere.

I guess I will keep digging until I find something.

OhSixTJ 06-27-2013 01:38 PM

Quote:

Originally Posted by biggus35 (Post 3904843)

Yes, I'm trying to find out where it goes inside the cab under the dash. Previous owner left a rat's nest of wires under the dash with an after market radio install and a satellite radio receiver and a light bar. I've disentangled most of the wires and removed what I could but cannot find the vacuum line. I'm thinking it was disconnected when they pulled all these new wires.

If someone knows where it connects under the dash please lest me know. I think it might be easier to find it if I know where it's supposed to be.

Thanks

Did you check behind the glove box?

biggus35 06-27-2013 01:42 PM

Quote:

Originally Posted by OhSixTJ (Post 3905010)
Did you check behind the glove box?

Yes, but cannot find it.

OhSixTJ 06-27-2013 02:10 PM

Quote:

Originally Posted by biggus35 (Post 3905026)

Yes, but cannot find it.

I'll look at mine when I get home from work

biggus35 06-27-2013 03:09 PM

Quote:

Originally Posted by OhSixTJ (Post 3905113)
I'll look at mine when I get home from work

Ok, so here's my notes from this afternoon:

1. Removing the vacuum from that hose switches the heater to the defroster so I'm thinking the hose IS connected to whatever it is supposed to connect to.

2. The same amount of Air flow is coming out of the dash vents regardless of what I set the selector knob to (AC, Defrost, or Heat).

2a. When on AC or Recirculate-AC the majority of the air flow is directed out the heater vents to the floor. It's probably around an 80/20 split with 80% coming out of the heater vents.

3. The hot/cold mix switch works but apparently does not close all the way because the air coming out of the heat vents (on the floor) is not as cold as the air coming out of the dash vents.

4.When I switch to 100% defrost the cold air is still coming out of the dash vents and the luke warm air comes out of the defrost vents. 100% Defrost is the only setting that cuts the air flow off from the heater vents.

I think I'll start another thread with this info.

thanks,

OhSixTJ 06-27-2013 04:22 PM

You should check the hose under the battery tray.i think that's a common problem spot. Mine was cracked. I duct taped it and all is well.

While it was broken I wasn't getting any air out of the dash, it was all defrost and floor. Doesn't take much to check it. I had to remove the battery and the tray it sits on.

Gary2 06-27-2013 08:09 PM

The other end of that vacuum line came off of the intake manifold on mine last week . When it was off I could not change where the AC or heat came out . The mode switch did nothing . I reconnected the line and it has been fine ever since so it does provide vacuum for the HVAC . I was starting the engine and I let off the key before it started completely and it kind of kicked back so to speak . That in turn blew the vacuum line off and blew soot up into the IAC which once cleaned out and is fine too. I don't know exactly where it connects to the HVAC at but all of those colored lines in your picture on the mode switch are vacuum lines which gets its vacuum from that small line you are asking about at some point

EDIT.. I just looked in the parts catalog and it shows the small line in question entering the fire wall as you can see in your picture and crosses over top of the HVAC housing . If you follow the colored vacuum lines in your picture you will eventually find a connection and the small one in question should be able to be located there. You could have a bad connection at the vacuum reservoir, the unit itself ( also part of Cruise control operation ) , their should also be a check valve along the line along wit the connection at the intake . I found the intake connection a little loose on mine so it now has a couple tiny zip ties on it as back up

biggus35 06-27-2013 09:18 PM

Sarge and Gary & others, thanks for the effort and the information. I think I'm beginning to see the bigger picture. I'm going to replace the vacuum reservoir for starters as it's only about $30.00 and if that doesn't help I'm going to replace the vacuum hoses and connections shown in the diagram. Even though I've inspected them very closely several times I think there must be a leak somewhere. When I first got the Jeep about a month ago I replaced other dry-rotted hoses but did not replace this main vacuum hose.

I will update the thread when I figure it out.

Hardermods 06-27-2013 09:32 PM

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Quote:

Originally Posted by OhSixTJ (Post 3905596)
You should check the hose under the battery tray.i think that's a common problem spot. Mine was cracked. I duct taped it and all is well.

While it was broken I wasn't getting any air out of the dash, it was all defrost and floor. Doesn't take much to check it. I had to remove the battery and the tray it sits on.

X2 on checking this line under the battery even if its connected make sure there are no cracks forming in it.

Easier than pulling the battery an tray, lay behind the right front tire and look up along the frame an you will see where that line connects to the vacuum canister


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