Heater Question

[djag12]

I have heat in the cab but only on passenger side feet and defrost. Is there a hose that may have come off? Or is it a vacuum issue? Also doesn't seem like the heater control works well as far as changing between vents, defrost, ect

[JeepcoMJ]

most likely a vacuum issue.

[Pete M]

Yup. Check your lines and check the vacuum ball in the front bumper for cracks.

[lawmanbsi]

having the same prob with mine. didn't know about the ball up front that could be an easy fix. I thought Iwas going to have to take the dash apart.

[Pete M]

Nah, you shouldn't have to. Most vacuum leaks are in the engine compartment where the lines are subject to greater wear and tear.

[djag12]

Looked at the little black ball. Mine looks new. How man lines go in and out of it?

[JeepcoMJ]

Looked at the little black ball. Mine looks new. How man lines go in and out of it?

 

there should be as many lines as there are holes :roll:

 

;)

[djag12]

Should have seen that coming :hmm:

[JeepcoMJ]

Should have seen that coming :hmm:

 

short answer;

 

2 small and 2 bigger holes if it's the egg-shaped one. the round one may be the same, but I don't recall. there were two different ones available and i'm not sure why

[djag12]

I don't have air so maybe the round one is for those of us with no air. Seem like I have one connector type wire and one hose type (which I would assume to be the vacuum hose)

[jaekl]

The vacuum reservoir had 2 hoses connected. (A single connection was used later) Your leak can be anywhere between the manifold and the heater. I had leaking hoses under the battery. You need to trace the lines back checking for vacuum at each connection in order to locate the loss of vacuum.

[djag12]

Looks like that's what I'll be doing on Saturday.

[james750]

Mine just started doing the same thing, but i think i know of where the leak is and have a question.

 

I just did a CAD bypass and have been trying to plug the vacuum holes that come from there, ive tryed shoving caps on it, shoving screws in, shoving caps, then screws then sealing it and it has worked ok for a while but after my sister hit a tree with it :roll: over spring on the pass. side bumper I'm worried that it could be the ball is cracked now.

 

what else can i do to seal the lower CAD hoses?

 

I'm going to go down and check the ball now.....

[Eagle]

Should have seen that coming :hmm:

 

short answer;

 

2 small and 2 bigger holes if it's the egg-shaped one. the round one may be the same, but I don't recall. there were two different ones available and i'm not sure why

The long one has two chambers, one for heater controls and one for cruise control. The round one is for vehicles w/o cruise.

[james750]

Well, Found the problem. The Heater hose was broken off right past the reservoir. I tried re-attaching it with just a soft hose but its still leaking, off to csk tommorow to get some fittings...

[mvusse]

Should have seen that coming :hmm:

 

short answer;

 

2 small and 2 bigger holes if it's the egg-shaped one. the round one may be the same, but I don't recall. there were two different ones available and i'm not sure why

The long one has two chambers, one for heater controls and one for cruise control. The round one is for vehicles w/o cruise.

 

Hmmm, my 87 had a round one with one big and one small hole. One line connected to all the vacuum stuff, one to just the heater controls. Also had a problem with the axle disco not disengaging.

 

When I replaced the bumper, the new one came with an oval one, much bigger. Since the mounting tabs were btoke on the old round one, I left the new one in the bumper, but, it only had 1 hole!

 

So I disconnected the heater one, since the controls didn't work anyway (well, the electrical part works, just not the vacuum) and put just the other one on.

 

Now my disco works great.

 

Fixing the heater controls are on the bottom of the list. When I do I'll find another vaccum source, or put a T in somewhere.

 

Byt what I'm getting at, why did my little round 87 MJ one have 2 holes, and my big oval newer (97+?) XJ Limited one has only 1. The bumper was factory color matched to the body.

[JeepcoMJ]

well, here's the thing.

 

your disco is NOT hooked up to that vacuum canister in any way, shape, or form. it just has hoses that run from the t-case to the disco. that's it.

 

so, somethings screwed up if that's working NOW and your heater controls arent...i'd say vacuum hoses are pretty screwed up on your rig.

[mvusse]

In that case, the new vacuum reservoir is a red herring in reference to the disco. Maybe it works correctly now because I've actually been using 4wd since I got it and engaged/disengaged it on average numerous times a day when there was snow. With bald tires I needed it more than I should have.

 

The truck had definitely been neglected, if not it's whole 21 years, at least the last few. The 4wd drive indicator light was on in 2wd, for a while and after using 4wd it'd take 2 days to go off. It would also take a few seconds to engage. Now it engages almost immediately and takes only a few seconds to disengage.

 

But if that has nothing to do with the vacuum reservoir, where does the transfer case get it's vacuum source for the disconnect? Or is it not vacuum operated like I though it was?

 

Heater control has different problems. Even with the line hooked up it would only blow at the defrost vent, and the temperature selector will not move from hot. The lever is physically stuck.

 

After the big and safety issues have been taken care of I'll pull it out of the dash and see what's going on. I'm sure the vacuum line is either clogged, cut or leaking, but there's something physically wrong with the controls as well. Since that is last on my list of things to do, once the weather warms up permanently I will probably jury rig the coolant shutoff valve to the off position until I get to it,

[Eagle]

You might just go to Homeless Depot or Lowe's and get a 3/4" lever-actuated ball valve. Solder a short length of tube into each side and mount it in-line in the hose to the heater core. Then you can turn the heat on or off manually any time you want.

[mvusse]

That might also work. A lot like the setup I saw in an 1977 IH school bus I drove for work during spring/early summer from 1990-92.

[mfpdm]

Here's a pic from the parts manual showing the different canisters. I doesn't list the long one with only one hole, however I saw one today at the JY on a 94 xj w/o cruise.

 

 

Here is also a thread from JF talking about this subject.

 

http://www.jeepforum.com/forum/showthread.php?t=520080

 

:cheers: