A/C Heater Problem

[danl72]

When I use the heater or defroster I don't feel anything coming out from the defroster or the vents with the heater on. It sounds like it is on, but I don't feel anything even when on high. Is there a vay to check if something is clogged? Is there a way to fix it myself? Thanks in advance.

 

[69MyWay]

I have the same problem with our 95 3500 truck. I can't figure it out short of tearing the dash out and looking around.

I will be keeping my eye on this thread to for some good ideas. It is so weird because you can hear the fan motor/blower running like the devil, but no air comes out the vents. If I shut if off for about 30 seconds or so and try again, it will usually work fine for a few more miles.

 

[c4c5specialist]

HI there,
You have a few different things to check, so please be patient with this thread.
First, all mode door operations are vacuum controlled, whether by the C60 or the CJ2 control system. Now, blower functions are all controlled by a electrical system.
Which system do you have??? Do you have digital display or not??
Next, have you had a leaking battery terminal ever in the vehicle???
Depending on what your answers are, will depend on the next course of action, as most mode door problems are due to an eaten away vacuum supply hose to the vacuum reservoir. This will occur from acid leaking under the battery tray, and onto the hose.
If you need to do a visual inspection, you can remove the batttery, and the 4 13mm bolts that hold the battery tray in, and pull the tray out.
From there, you can look down, see the PCM, the TAC module, once there, follow the frame rail back, towards the rear of the car. Approx 4 inches back, you will see a black plastic tank, with a hose coming out of it, this hose is your supply line, look to see for damage.
Please let us know what you have, besttoyou, c4c5

 

[danl72]

c4c5specialist,
The answer to your question is yes to the digital display and yes to the battery leak. I caught it early and replaced it with an Optima battery. It was a Delco leaking from the positive terminal. I did do a check by taking the battery tray out and I did not notice anything. I will check again though as I may have over looked something. I will keep you updated. Thanks for the advice.

 

[danl72]

c4c5specialist,
Ok, I checked the hose and it doesn't look like it has any holes in it, at least from where I can see it. Should I replace it to play it safe, and if so where can I get the hose from, dealer or auto parts store. Thanks in advance.

 

[c4c5specialist]

Hi there,
What I would do, is to just sit the battery tray in, and then the battery. Start the car, and listen for a hiss, coming from that area.
It is a simple test, and you will be able to find it no problem.
If you hear anything at all, from that area, you can just slide the bat, and the tray right out.
Let me know what you have, c4c5

 

[danl72]

Ok, I started the car and heard a hiss from the area of the battery. I guess I need to replace the hose. Is there anything else that needs to be done? Thanks in advance.

 

[c4c5specialist]

H ithere,
Nope. That will be all. Just remember, make sure that you have the bad piece in your hand, before reinstalling the tray and battery.
And let us know how you make out, c4c5

 

[danl72]

Quick question, What size is the hose, 1/2, 3/8? Thanks in advance.

 

[c4c5specialist]

Hi there,
It will be 1.4 in plastic hard line.
You can obtain line in the Motormite automotive parts line.
It will be called VACU-TITE.
Besttoyou, c4c5

 

[danl72]

Hi there,
It will be 1.4 in plastic hard line.
You can obtain line in the Motormite automotive parts line.
It will be called VACU-TITE.
Besttoyou, c4c5

Thank you.

 

[danl72]

Ok. now my A/C is working, but not the problem seems to be that the air is coming in from the defroster. A little amount of air comes in from the vents. I change the mode settings and it still comes in from the defroster with little air coming in from whatever mode I put. For example I set it for floor and it comes in mostly from the defroser and a little air comes in from the floor, same with all of the settings. Any help is greatly welcome and needed. Thanks in advance.

 

[69MyWay]

Don't know for sure on the C5, but most cars go to default defrost setting when they loose the vacuum signal. You might now have a pinched line in there under the battery.

 

[danl72]

Thanks I will check it out, but I did not do anything to it. I will check it out anyway, you never know. Thanks again.

 

[gazza]

This thread really helped me. My A/C had the exact same problem i.e. mode button would not change airflow from the failsafe of windshield with some at vents and floor. After reading about the battery leak and corrosion of the vacu line I removed the battery to find definate evidence of battery leaking. Removing the battery box/shelf was easy (4 13mm bolts) and then finding the hard vacu-line was simple enough but locating the resovoir was not so easy since it is very well hidden under the passenger wing near the door pillar.

Feeling along the hard line I had several holes and so I cut out that section (about 1.5 inch) with a sharp pair of wire cutters and then joined the two ends with some heavy duty silicone fuel tubing I use on my model helicopters pressurised fuel systems. This suff is tough, rigid enough to hold the vacuum and makes a killer seal.

Problem solved !

If you want to do the same take a piece of the rigid line to your local model shop and ask for some silicone fuel tube that fits tight. Should cost less than a $1 (and your time of course).

 

[HallenTi]

I too found that the battery had leaked, putting a couple of holes into the hard plastic line. I cut out the section (about an inch or so) and used the idea of the model engine silicone hose and that worked very well. I carefully checked the rest of the hard line as far as I could see and reach just to be safe and found no additional holes.

Once I replaced the bad piece, I too still have little air flow out of the floor, vent or defroster vents, even with the fan on fill. I have the electronic dual-control electronic unit. The fan goes through all the steps up to full, and you can hear that it is really going on the full setting. Just not much air flow. Other than the hard line to the reservoir, is there an additional area that could have a vacuum leak (I doubt the reservoir could be cracked, as I expect there would be no flow and a major hissing sound).

I find that it makes little difference what temperature is set, nor does it change between fresh and recirculated air.

Any additional help would be appreciated.

 

[HallenTi]

I decided that I must have missed something the first time, so took out the battery and box and checked the hard plastic hose completely down to the reservoir. I felt what could have been glue on the hose or a melted section, so carefully wiggled the rubber elbow that is molded on the end of the hard plastic hose loose from the reservoir. When I could get the hose in a better position to inspect it, I found another breach. I again cut out the bad section, patched it with the silicone model engine fuel hose, and the whole thing works just like I remember before the battery leak. Thanks for all the suggestions and the help. Tim